Uncaught Error: Header must provide a Content-Length property.

[Enter steps to reproduce:]

1. ...
2. ...

**Atom**: 1.26.1 x64
**Electron**: 1.7.11
**OS**: Mac OS X 10.13.4
**Thrown From**: [ide-python](https://github.com/lgeiger/ide-python) package 0.9.2

### Stack Trace

Uncaught Error: Header must provide a Content-Length property.

```
At /Users/jasonkuhrt/.atom/packages/ide-python/node_modules/vscode-jsonrpc/lib/messageReader.js:200

Error: Header must provide a Content-Length property.
at StreamMessageReader.onData (/packages/ide-python/node_modules/vscode-jsonrpc/lib/messageReader.js:200:27)
at /packages/ide-python/node_modules/vscode-jsonrpc/lib/messageReader.js:185:19)
at emitOne (events.js:96:13)
at Socket.emit (events.js:191:7)
at readableAddChunk (_stream_readable.js:178:18)
at Socket.Readable.push (_stream_readable.js:136:10)
at Pipe.onread (net.js:560:20)
```

### Commands

```
2x -6:02.3.0 pane:show-previous-item (input.hidden-input)
-5:58.6.0 vim-mode-plus:find (input.hidden-input)
2x -5:58.2.0 vim-mode-plus:move-to-pair (input.hidden-input)
-5:43.2.0 vim-mode-plus:move-to-first-character-of-line (input.hidden-input)
-5:36.8.0 vim-mode-plus:insert-above-with-newline (input.hidden-input)
-5:36.1.0 exit-insert-mode-if-preceded-by-k (input.hidden-input)
-5:36.1.0 vim-mode-plus:activate-normal-mode (atom-text-editor.editor.vim-mode-plus.is-focused.insert-mode)
2x -5:36 vim-mode-plus:delete (input.hidden-input)
-5:35.7.0 vim-mode-plus:move-up (input.hidden-input)
-5:35.4.0 vim-mode-plus:move-down (input.hidden-input)
-5:35.3.0 vim-mode-plus:move-to-end-of-word (input.hidden-input)
-5:35.1.0 vim-mode-plus:move-down (input.hidden-input)
-5:34.6.0 vim-mode-plus:move-to-first-character-of-line (input.hidden-input)
4x -5:33.9.0 vim-mode-plus:move-down (input.hidden-input)
-5:30.9.0 core:save (input.hidden-input)
2x -0:15.6.0 github:discard-changes-in-selected-files (span.github-FilePatchListView-path)
```

### Non-Core Packages

```
asciidoc-assistant 0.2.2
asciidoc-image-helper 1.0.0
asciidoc-preview 2.11.0
atom-autocomplete-php 0.25.6
atom-beautify 0.32.2
atom-ide-ui 0.11.1
atom-ternjs 0.18.3
atom-typescript 12.4.1
atomatigit 1.5.5
auto-detect-indentation 1.3.0
auto-update-packages 1.0.1
autocomplete-asciidoc 0.1.2
autocomplete-haskell 1.0.1
autocomplete-json 5.5.2
autocomplete-modules 2.0.0
busy-signal 1.4.3
color-picker 2.3.0
docblockr 0.13.7
docker 0.8.0
dockerletion 0.2.0
flow-ide 1.11.0
gist-it 0.9.2
haskell-ghc-mod 2.2.3
highlight-selected 0.13.1
hyperclick 0.0.0
ide-haskell 2.3.1
ide-haskell-cabal 2.2.0
ide-haskell-hasktags 0.0.15
ide-haskell-repl 0.8.0
ide-json 0.2.1
ide-python 0.9.2
ide-yaml 0.4.3
intentions 1.1.5
js-hyperclick 1.13.0
language-apache 1.8.0
language-asciidoc 1.11.0
language-diff 0.7.0
language-docker 1.1.8
language-elm 1.5.0
language-env 0.2.0
language-haskell 1.17.6
language-jade 0.7.3
language-protobuf 0.7.1
language-purescript 0.8.3
language-terraform 0.8.1
language-viml 1.1.8
language-vue 0.23.1
linter 2.2.0
linter-coffeelint 2.0.0
linter-docker 0.3.2
linter-eslint 8.4.1
linter-flow 5.6.1
linter-hlint 2.0.0
linter-jsonlint 1.3.0
linter-php 1.5.1
linter-pylama 0.9.5
linter-shellcheck 1.4.7
linter-tslint 1.9.1
linter-ui-default 1.7.1
nucleus-dark-ui 0.12.3
pigments 0.40.2
prettier-atom 0.53.0
project-manager 3.3.5
seti-syntax 1.1.3
Sublime-Style-Column-Selection 1.7.4
sync-settings 0.8.6
todo-show 2.3.0
vim-mode-plus 1.32.0
wordcount 2.10.4
Zen 0.18.0
```