FRE-600: Fix code review blockers

- Consolidated duplicate UndoManagers to single instance
- Fixed connection promise to only resolve on 'connected' status
- Fixed WebSocketProvider import (WebsocketProvider)
- Added proper doc.destroy() cleanup
- Renamed isPresenceInitialized property to avoid conflict

Co-Authored-By: Paperclip <noreply@paperclip.ing>

node_modules/level-iterator-stream/CHANGELOG.md

@@ -0,0 +1,189 @@
+# Changelog
+
+_**If you are upgrading:** please see [`UPGRADING.md`](UPGRADING.md)._
+
+## [4.0.2] - 2019-10-05
+
+### Changed
+
+- Upgrade `hallmark` devDependency from `^0.1.0` to `^2.0.0` ([#58](https://github.com/Level/iterator-stream/issues/58), [#61](https://github.com/Level/iterator-stream/issues/61)) ([**@vweevers**](https://github.com/vweevers))
+- Upgrade `standard` devDependency from `^12.0.0` to `^14.0.0` ([#57](https://github.com/Level/iterator-stream/issues/57), [#60](https://github.com/Level/iterator-stream/issues/60)) ([**@vweevers**](https://github.com/vweevers))
+- Upgrade `nyc` devDependency from `^13.2.0` to `^14.0.0` ([#55](https://github.com/Level/iterator-stream/issues/55)) ([**@vweevers**](https://github.com/vweevers))
+- Tweak tests ([#62](https://github.com/Level/iterator-stream/issues/62)) ([**@vweevers**](https://github.com/vweevers))
+
+### Added
+
+- Test that stream keeps a reference to the iterator ([`16a4dd5`](https://github.com/Level/iterator-stream/commit/16a4dd5)) ([**@vweevers**](https://github.com/vweevers))
+
+## [4.0.1] - 2019-03-30
+
+### Changed
+
+- Upgrade `leveldown` devDependency from `^4.0.0` to `^5.0.0` ([#52](https://github.com/Level/iterator-stream/issues/52)) ([**@vweevers**](https://github.com/vweevers))
+- Upgrade `nyc` devDependency from `^12.0.2` to `^13.2.0` ([#51](https://github.com/Level/iterator-stream/issues/51)) ([**@vweevers**](https://github.com/vweevers))
+- Apply common project tweaks ([#49](https://github.com/Level/iterator-stream/issues/49), [#50](https://github.com/Level/iterator-stream/issues/50), [`fece33a`](https://github.com/Level/iterator-stream/commit/fece33a), [`b3b3b6c`](https://github.com/Level/iterator-stream/commit/b3b3b6c)) ([**@vweevers**](https://github.com/vweevers))
+
+### Fixed
+
+- Fix reference to undefined definition in `CHANGELOG.md` ([`aa88961`](https://github.com/Level/iterator-stream/commit/aa88961)) ([**@vweevers**](https://github.com/vweevers))
+
+## [4.0.0] - 2018-12-17
+
+### Changed
+
+- Upgrade `through2` devDependency from `^2.0.0` to `^3.0.0` ([**@vweevers**](https://github.com/vweevers))
+- Upgrade `readable-stream` dependency from `^2.0.5` to `^3.0.2` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Upgrade `standard` devDependency from `^11.0.0` to `^12.0.0` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Added
+
+- Add `nyc` and `coveralls` ([#39](https://github.com/Level/iterator-stream/issues/39)) ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Removed
+
+- Remove node 9 ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+## [3.0.1] - 2018-10-18
+
+### Fixed
+
+- Bump `readable-stream` from `^2.0` to `^2.3` to prevent npm dedupe and ensure it has `#destroy()` ([**@vweevers**](https://github.com/vweevers))
+
+## [3.0.0] - 2018-06-28
+
+### Changed
+
+- Proper destroy ([#34](https://github.com/Level/iterator-stream/issues/34)) ([**@vweevers**](https://github.com/vweevers))
+
+### Removed
+
+- Remove node 4 ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+## [2.0.3] - 2018-06-28
+
+### Fixed
+
+- Revert proper destroy ([#34](https://github.com/Level/iterator-stream/issues/34)) ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+**Historical Note** The previous release was meant to restore node 4 and included an additional change by mistake.
+
+## [2.0.2] - 2018-06-28
+
+### Changed
+
+- Restore node 4 ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Proper destroy ([#34](https://github.com/Level/iterator-stream/issues/34)) ([**@vweevers**](https://github.com/vweevers))
+
+**Historical Note** We made a mistake releasing `v2.0.1` with the `engines` field in `package.json` set to node 6 as minimal version. This caused problems for users of yarn. We therefore released `v2.0.2` which restored node 4 and a new major directly after this.
+
+## [2.0.1] - 2018-06-10
+
+### Changed
+
+- Upgrade `leveldown` devDependency from `^1.4.1` to `^4.0.0` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Upgrade `standard` devDependency from `^10.0.3` to `^11.0.0` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Added
+
+- Add node 9 and 10 to Travis ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Add `UPGRADING.md` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Removed
+
+- Remove node 7 from Travis ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+## [2.0.0] - 2017-08-28
+
+### Changed
+
+- Upgrade `readable-stream` from `^1.0.33` to `^2.0.5` ([**@greenkeeper**](https://github.com/greenkeeper), [**@ralphtheninja**](https://github.com/ralphtheninja))
+- Upgrade `tape` devDependency from `^3.5.0` to `^4.4.0` ([**@greenkeeper**](https://github.com/greenkeeper), [**@ralphtheninja**](https://github.com/ralphtheninja))
+- Upgrade `through2` devDependency from `^0.6.3` to `^2.0.0` ([**@greenkeeper**](https://github.com/greenkeeper), [**@ralphtheninja**](https://github.com/ralphtheninja))
+- Upgrade `leveldown` devDependency from `^0.10.4` to `^1.4.1` ([**@juliangruber**](https://github.com/juliangruber))
+- Update copyright year to 2017 ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Update README example using `standard` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Added
+
+- Add node 6 to Travis ([**@greenkeeper**](https://github.com/greenkeeper), [**@juliangruber**](https://github.com/juliangruber))
+- Add node 7 and 8 to Travis ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Add Greenkeeper ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Add `standard` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Test `.destroy()` during and after `iterator.next()` ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Removed
+
+- Remove node 0.10, 0.12 and iojs from Travis ([**@greenkeeper**](https://github.com/greenkeeper), [**@juliangruber**](https://github.com/juliangruber))
+- Remove encodings ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Remove Makefile ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+## [1.3.1] - 2015-08-17
+
+### Changed
+
+- Update `.repository` path in `package.json` ([**@timoxley**](https://github.com/timoxley))
+
+### Fixed
+
+- Use `level-codec` from npm ([**@juliangruber**](https://github.com/juliangruber))
+
+## [1.3.0] - 2015-05-05
+
+### Fixed
+
+- Emit `'close'` after `'error'` ([**@juliangruber**](https://github.com/juliangruber))
+
+## [1.2.0] - 2015-05-04
+
+### Added
+
+- Add `.decoder` option to constructor for decoding keys and values ([**@juliangruber**](https://github.com/juliangruber))
+
+## [1.1.1] - 2015-03-29
+
+### Added
+
+- Enable Travis and add node 0.10, 0.12 and iojs ([**@ralphtheninja**](https://github.com/ralphtheninja))
+- Add MIT license ([**@ralphtheninja**](https://github.com/ralphtheninja))
+
+### Fixed
+
+- Fix race condition in `.destroy()` ([**@juliangruber**](https://github.com/juliangruber))
+
+## [1.1.0] - 2015-03-29
+
+### Added
+
+- Add `.destroy()` ([**@juliangruber**](https://github.com/juliangruber))
+
+## 1.0.0 - 2015-03-29
+
+:seedling: Initial release.
+
+[4.0.2]: https://github.com/Level/iterator-stream/compare/v4.0.1...v4.0.2
+
+[4.0.1]: https://github.com/Level/iterator-stream/compare/v4.0.0...v4.0.1
+
+[4.0.0]: https://github.com/Level/iterator-stream/compare/v3.0.1...v4.0.0
+
+[3.0.1]: https://github.com/Level/iterator-stream/compare/v3.0.0...v3.0.1
+
+[3.0.0]: https://github.com/Level/iterator-stream/compare/v2.0.3...v3.0.0
+
+[2.0.3]: https://github.com/Level/iterator-stream/compare/v2.0.2...v2.0.3
+
+[2.0.2]: https://github.com/Level/iterator-stream/compare/v2.0.1...v2.0.2
+
+[2.0.1]: https://github.com/Level/iterator-stream/compare/v2.0.0...v2.0.1
+
+[2.0.0]: https://github.com/Level/iterator-stream/compare/v1.3.1...v2.0.0
+
+[1.3.1]: https://github.com/Level/iterator-stream/compare/v1.3.0...v1.3.1
+
+[1.3.0]: https://github.com/Level/iterator-stream/compare/v1.2.0...v1.3.0
+
+[1.2.0]: https://github.com/Level/iterator-stream/compare/v1.1.1...v1.2.0
+
+[1.1.1]: https://github.com/Level/iterator-stream/compare/v1.1.0...v1.1.1
+
+[1.1.0]: https://github.com/Level/iterator-stream/compare/v1.0.0...v1.1.0

node_modules/level-iterator-stream/CONTRIBUTORS.md

@@ -0,0 +1,8 @@
+# Contributors
+
+| Name                 | GitHub                                                 | Social                                                        |
+| :------------------- | :----------------------------------------------------- | :------------------------------------------------------------ |
+| **Lars-Magnus Skog** | [**@ralphtheninja**](https://github.com/ralphtheninja) | [**@ralph@social.weho.st**](https://social.weho.st/@ralph)    |
+| **Julian Gruber**    | [**@juliangruber**](https://github.com/juliangruber)   | [**@juliangruber@twitter**](https://twitter.com/juliangruber) |
+| **Vincent Weevers**  | [**@vweevers**](https://github.com/vweevers)           | [**@vweevers@twitter**](https://twitter.com/vweevers)         |
+| **Tim Oxley**        | [**@timoxley**](https://github.com/timoxley)           | [**@secoif@twitter**](https://twitter.com/secoif)             |

node_modules/level-iterator-stream/LICENSE.md

@@ -0,0 +1,21 @@
+# The MIT License (MIT)
+
+**Copyright © 2012-present [Contributors](CONTRIBUTORS.md).**
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

node_modules/level-iterator-stream/README.md

@@ -0,0 +1,76 @@
+# level-iterator-stream
+
+> Turn an [abstract-leveldown](https://github.com/Level/abstract-leveldown) iterator into a readable stream.
+
+[![level badge][level-badge]](https://github.com/Level/awesome)
+[![npm](https://img.shields.io/npm/v/level-iterator-stream.svg?label=&logo=npm)](https://www.npmjs.com/package/level-iterator-stream)
+[![Node version](https://img.shields.io/node/v/level-iterator-stream.svg)](https://www.npmjs.com/package/level-iterator-stream)
+[![Travis](https://img.shields.io/travis/com/Level/iterator-stream.svg?logo=travis&label=)](https://travis-ci.com/Level/iterator-stream)
+[![Coverage Status](https://coveralls.io/repos/github/Level/iterator-stream/badge.svg)](https://coveralls.io/github/Level/iterator-stream)
+[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
+[![npm](https://img.shields.io/npm/dm/level-iterator-stream.svg?label=dl)](https://www.npmjs.com/package/level-iterator-stream)
+[![Backers on Open Collective](https://opencollective.com/level/backers/badge.svg?color=orange)](#backers)
+[![Sponsors on Open Collective](https://opencollective.com/level/sponsors/badge.svg?color=orange)](#sponsors)
+
+## Usage
+
+**If you are upgrading:** please see [UPGRADING.md](UPGRADING.md).
+
+```js
+var iteratorStream = require('level-iterator-stream')
+var leveldown = require('leveldown')
+
+var db = leveldown(__dirname + '/db')
+db.open(function (err) {
+  if (err) throw err
+
+  var stream = iteratorStream(db.iterator())
+  stream.on('data', function (kv) {
+    console.log('%s -> %s', kv.key, kv.value)
+  })
+})
+```
+
+## Installation
+
+```bash
+$ npm install level-iterator-stream
+```
+
+## API
+
+### `stream = iteratorStream(iterator[, options])`
+
+Create a readable stream from `iterator`. `options` are passed down to the `require('readable-stream').Readable` constructor, with `objectMode` forced to `true`.
+
+Set `options.keys` or `options.values` to `false` to only get values / keys. Otherwise receive `{ key, value }` objects.
+
+When the stream ends, the `iterator` will be closed and afterwards a `"close"` event emitted.
+
+`.destroy()` will force close the underlying iterator.
+
+## Contributing
+
+[`Level/iterator-stream`](https://github.com/Level/iterator-stream) is an **OPEN Open Source Project**. This means that:
+
+> Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.
+
+See the [Contribution Guide](https://github.com/Level/community/blob/master/CONTRIBUTING.md) for more details.
+
+## Donate
+
+To sustain [`Level`](https://github.com/Level) and its activities, become a backer or sponsor on [Open Collective](https://opencollective.com/level). Your logo or avatar will be displayed on our 28+ [GitHub repositories](https://github.com/Level) and [npm](https://www.npmjs.com/) packages. 💖
+
+### Backers
+
+[![Open Collective backers](https://opencollective.com/level/backers.svg?width=890)](https://opencollective.com/level)
+
+### Sponsors
+
+[![Open Collective sponsors](https://opencollective.com/level/sponsors.svg?width=890)](https://opencollective.com/level)
+
+## License
+
+[MIT](LICENSE.md) © 2012-present [Contributors](CONTRIBUTORS.md).
+
+[level-badge]: https://leveljs.org/img/badge.svg

node_modules/level-iterator-stream/UPGRADING.md

@@ -0,0 +1,22 @@
+# Upgrade Guide
+
+This document describes breaking changes and how to upgrade. For a complete list of changes including minor and patch releases, please refer to the [changelog](CHANGELOG.md).
+
+## v4
+
+Upgraded to [`readable-stream@3`](https://github.com/nodejs/readable-stream#version-3xx) which contains several substantial changes and improvements. Since `level-iterator-stream` derives from `readable-stream` we decided to bump major as well.
+
+## v3
+
+Removed support for node 4.
+
+## v2
+
+Encodings were factored out from `levelup` into `encoding-down` and in that process they were removed from this module as well. For more information, please check the corresponding `CHANGELOG.md` for:
+
+- [`levelup`](https://github.com/Level/levelup/blob/master/CHANGELOG.md)
+- [`encoding-down`](https://github.com/Level/encoding-down/blob/master/CHANGELOG.md)
+
+If your code relies on `options.decoder` for decoding keys and values you need to handle this yourself, e.g. by a transform stream or similar.
+
+Support for node 0.10, 0.12 and iojs was also dropped.

node_modules/level-iterator-stream/example.js

@@ -0,0 +1,26 @@
+var iteratorStream = require('./')
+var leveldown = require('leveldown')
+var path = require('path')
+
+var db = leveldown(path.join(__dirname, 'db'))
+db.open(function (err) {
+  if (err) throw err
+
+  var ops = []
+  for (var i = 0; i < 1000; i++) {
+    ops.push({
+      type: 'put',
+      key: String(Math.random()),
+      value: String(Math.random())
+    })
+  }
+
+  db.batch(ops, function (err) {
+    if (err) throw err
+
+    var stream = iteratorStream(db.iterator())
+    stream.on('data', function (kv) {
+      console.log('%s -> %s', kv.key, kv.value)
+    })
+  })
+})

node_modules/level-iterator-stream/index.js

@@ -0,0 +1,44 @@
+var inherits = require('inherits')
+var Readable = require('readable-stream').Readable
+var extend = require('xtend')
+
+module.exports = ReadStream
+inherits(ReadStream, Readable)
+
+function ReadStream (iterator, options) {
+  if (!(this instanceof ReadStream)) return new ReadStream(iterator, options)
+  options = options || {}
+  Readable.call(this, extend(options, {
+    objectMode: true
+  }))
+  this._iterator = iterator
+  this._options = options
+  this.on('end', this.destroy.bind(this, null, null))
+}
+
+ReadStream.prototype._read = function () {
+  var self = this
+  var options = this._options
+  if (this.destroyed) return
+
+  this._iterator.next(function (err, key, value) {
+    if (self.destroyed) return
+    if (err) return self.destroy(err)
+
+    if (key === undefined && value === undefined) {
+      self.push(null)
+    } else if (options.keys !== false && options.values === false) {
+      self.push(key)
+    } else if (options.keys === false && options.values !== false) {
+      self.push(value)
+    } else {
+      self.push({ key: key, value: value })
+    }
+  })
+}
+
+ReadStream.prototype._destroy = function (err, callback) {
+  this._iterator.end(function (err2) {
+    callback(err || err2)
+  })
+}

node_modules/level-iterator-stream/package.json

@@ -0,0 +1,48 @@
+{
+  "name": "level-iterator-stream",
+  "version": "4.0.2",
+  "description": "Turn an abstract-leveldown iterator into a readable stream",
+  "license": "MIT",
+  "scripts": {
+    "test": "standard && hallmark && (nyc -s node test.js | faucet) && nyc report",
+    "coverage": "nyc report --reporter=text-lcov | coveralls",
+    "hallmark": "hallmark --fix",
+    "dependency-check": "dependency-check . test.js",
+    "prepublishOnly": "npm run dependency-check"
+  },
+  "dependencies": {
+    "inherits": "^2.0.4",
+    "readable-stream": "^3.4.0",
+    "xtend": "^4.0.2"
+  },
+  "devDependencies": {
+    "coveralls": "^3.0.2",
+    "dependency-check": "^3.3.0",
+    "faucet": "^0.0.1",
+    "hallmark": "^2.0.0",
+    "level-community": "^3.0.0",
+    "leveldown": "^5.0.0",
+    "nyc": "^14.0.0",
+    "secret-event-listener": "^1.0.0",
+    "standard": "^14.0.0",
+    "tape": "^4.4.0",
+    "tempy": "0.2.1",
+    "through2": "^3.0.0"
+  },
+  "hallmark": {
+    "community": "level-community"
+  },
+  "repository": "Level/iterator-stream",
+  "homepage": "https://github.com/Level/iterator-stream",
+  "keywords": [
+    "level"
+  ],
+  "engines": {
+    "node": ">=6"
+  },
+  "greenkeeper": {
+    "ignore": [
+      "tempy"
+    ]
+  }
+}

node_modules/level-iterator-stream/test.js

@@ -0,0 +1,371 @@
+var test = require('tape')
+var leveldown = require('leveldown')
+var iteratorStream = require('./')
+var through2 = require('through2')
+var tempy = require('tempy')
+var addSecretListener = require('secret-event-listener')
+
+var db
+var data = [
+  { type: 'put', key: 'foobatch1', value: 'bar1' },
+  { type: 'put', key: 'foobatch2', value: 'bar2' },
+  { type: 'put', key: 'foobatch3', value: 'bar3' }
+]
+
+test('setup', function (t) {
+  db = leveldown(tempy.directory())
+  db.open(function (err) {
+    t.error(err, 'no error')
+    db.batch(data, function (err) {
+      t.error(err, 'no error')
+      t.end()
+    })
+  })
+})
+
+test('keys and values', function (t) {
+  var idx = 0
+  var stream = iteratorStream(db.iterator())
+  stream.pipe(through2.obj(function (kv, _, done) {
+    t.ok(Buffer.isBuffer(kv.key))
+    t.ok(Buffer.isBuffer(kv.value))
+    t.equal(kv.key.toString(), data[idx].key)
+    t.equal(kv.value.toString(), data[idx].value)
+    idx++
+    done()
+  }, function () {
+    t.equal(idx, data.length)
+    stream.on('close', function () {
+      t.end()
+    })
+  }))
+})
+
+test('normal event order', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order.filter(withoutDataEvents), ['_end', 'end', 'close'])
+    t.end()
+  })
+
+  stream.resume()
+})
+
+test('error from iterator.next', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'error: next', 'close'], 'event order')
+    t.end()
+  })
+
+  iterator.next = function (cb) {
+    process.nextTick(cb, new Error('next'))
+  }
+
+  stream.resume()
+})
+
+test('error from iterator end', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+  var _end = iterator._end
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order.filter(withoutDataEvents), ['_end', 'end', 'error: end', 'close'])
+    t.end()
+  })
+
+  iterator._end = function (cb) {
+    order.push('_end')
+    _end.call(this, function (err) {
+      t.ifError(err)
+      cb(new Error('end'))
+    })
+  }
+
+  stream.resume()
+})
+
+test('.destroy', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'close'])
+    t.end()
+  })
+
+  stream.destroy()
+})
+
+test('.destroy(err)', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'error: user', 'close'])
+    t.end()
+  })
+
+  stream.destroy(new Error('user'))
+})
+
+test('.destroy(err, callback)', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'callback', 'close'])
+    t.end()
+  })
+
+  stream.destroy(new Error('user'), function (err) {
+    order.push('callback')
+    t.is(err.message, 'user', 'got error')
+  })
+})
+
+test('.destroy(null, callback)', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'callback', 'close'])
+    t.end()
+  })
+
+  stream.destroy(null, function (err) {
+    order.push('callback')
+    t.ifError(err, 'no error')
+  })
+})
+
+test('.destroy() during iterator.next', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'close'], 'event order')
+    t.end()
+  })
+
+  iterator.next = function () {
+    stream.destroy()
+  }
+
+  stream.resume()
+})
+
+test('.destroy(err) during iterator.next', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'error: user', 'close'], 'event order')
+    t.end()
+  })
+
+  iterator.next = function (cb) {
+    stream.destroy(new Error('user'))
+  }
+
+  stream.resume()
+})
+
+test('.destroy(err, callback) during iterator.next', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'callback', 'close'], 'event order')
+    t.end()
+  })
+
+  iterator.next = function (cb) {
+    stream.destroy(new Error('user'), function (err) {
+      order.push('callback')
+      t.is(err.message, 'user', 'got error')
+    })
+  }
+
+  stream.resume()
+})
+
+test('.destroy(null, callback) during iterator.next', function (t) {
+  var iterator = db.iterator()
+  var stream = iteratorStream(iterator)
+
+  var order = monitor(iterator, stream, function () {
+    t.same(order, ['_end', 'callback', 'close'], 'event order')
+    t.end()
+  })
+
+  iterator.next = function (cb) {
+    stream.destroy(null, function (err) {
+      order.push('callback')
+      t.ifError(err, 'no error')
+    })
+  }
+
+  stream.resume()
+})
+
+test('.destroy during iterator.next 1', function (t) {
+  var stream
+  var iterator = db.iterator()
+  var next = iterator.next.bind(iterator)
+  iterator.next = function (cb) {
+    t.pass('should be called once')
+    next(cb)
+    stream.destroy()
+  }
+  stream = iteratorStream(iterator)
+  stream.on('data', function (data) {
+    t.fail('should not be called')
+  })
+  stream.on('close', t.end.bind(t))
+})
+
+test('.destroy during iterator.next 2', function (t) {
+  var stream
+  var iterator = db.iterator()
+  var next = iterator.next.bind(iterator)
+  var count = 0
+  iterator.next = function (cb) {
+    t.pass('should be called')
+    next(cb)
+    if (++count === 2) {
+      stream.destroy()
+    }
+  }
+  stream = iteratorStream(iterator)
+  stream.on('data', function (data) {
+    t.pass('should be called')
+  })
+  stream.on('close', t.end.bind(t))
+})
+
+test('.destroy after iterator.next 1', function (t) {
+  var stream
+  var iterator = db.iterator()
+  var next = iterator.next.bind(iterator)
+  iterator.next = function (cb) {
+    next(function (err, key, value) {
+      stream.destroy()
+      cb(err, key, value)
+      t.pass('should be called')
+    })
+  }
+  stream = iteratorStream(iterator)
+  stream.on('data', function (data) {
+    t.fail('should not be called')
+  })
+  stream.on('close', t.end.bind(t))
+})
+
+test('.destroy after iterator.next 2', function (t) {
+  var stream
+  var iterator = db.iterator()
+  var next = iterator.next.bind(iterator)
+  var count = 0
+  iterator.next = function (cb) {
+    next(function (err, key, value) {
+      if (++count === 2) {
+        stream.destroy()
+      }
+      cb(err, key, value)
+      t.pass('should be called')
+    })
+  }
+  stream = iteratorStream(iterator)
+  stream.on('data', function (data) {
+    t.pass('should be called')
+  })
+  stream.on('close', t.end.bind(t))
+})
+
+test('keys=false', function (t) {
+  var stream = iteratorStream(db.iterator(), { keys: false })
+  stream.once('data', function (value) {
+    stream.destroy()
+    t.equal(value.toString(), 'bar1')
+    t.end()
+  })
+})
+
+test('values=false', function (t) {
+  var stream = iteratorStream(db.iterator(), { values: false })
+  stream.once('data', function (key) {
+    stream.destroy()
+    t.equal(key.toString(), 'foobatch1')
+    t.end()
+  })
+})
+
+// It's important to keep a reference to the iterator at least until we end,
+// to prevent GC of the iterator and therefor its db (esp. for native addons).
+test('keeps a reference to the iterator', function (t) {
+  var it = db.iterator()
+  var stream = iteratorStream(it)
+
+  stream.on('close', function () {
+    t.is(stream._iterator, it, 'has reference')
+    t.end()
+  })
+
+  stream.resume()
+})
+
+// Note: also serves as teardown of above tests
+test('it is safe to close db on end of stream', function (t) {
+  // Set highWaterMark to 0 so that we don't preemptively fetch.
+  var it = db.iterator({ highWaterMark: 0 })
+  var stream = iteratorStream(it)
+
+  stream.on('end', function () {
+    // Although the underlying iterator is still alive at this point (before
+    // the 'close' event has been emitted) it's safe to close the db because
+    // leveldown (v5) ends any open iterators before closing.
+    db.close(function (err) {
+      t.ifError(err, 'no error')
+      t.end()
+    })
+  })
+
+  stream.resume()
+})
+
+function monitor (iterator, stream, onClose) {
+  var order = []
+
+  ;['_next', '_end'].forEach(function (method) {
+    var original = iterator[method]
+
+    iterator[method] = function () {
+      order.push(method)
+      original.apply(this, arguments)
+    }
+  })
+
+  ;['data', 'end', 'error', 'close'].forEach(function (event) {
+    // Add listener without side effects (like triggering flowing mode)
+    addSecretListener(stream, event, function (err) {
+      if (event === 'error') order.push('error: ' + err.message)
+      else order.push(event)
+    })
+  })
+
+  if (onClose) {
+    addSecretListener(stream, 'close', onClose)
+  }
+
+  return order
+}
+
+function withoutDataEvents (event) {
+  return event !== '_next' && event !== 'data'
+}