It addresses an issue I had running it on macos. A hotfix is applied which I do not know if it applies to other operating systems etc. https://github.com/mauritsvdvijgh/flutter-reload.vim/issues/1

Forked from: https://github.com/hankchiutw/flutter-reload.vim

Reload flutter when saving a dart file without using --pid-file option.

1. Add Plug 'mauritsvdvijgh/flutter-reload.vim' to your vimrc file.
2. Reload your vimrc or restart
3. Run :PlugInstall

1. Add Plugin 'mauritsvdvijgh/flutter-reload.vim' to your vimrc file.
2. Reload your vimrc or restart
3. Run :BundleInstall

1. Add NeoBundle 'mauritsvdvijgh/flutter-reload.vim' to your vimrc file.
2. Reload your vimrc or restart
3. Run :NeoUpdate

cd ~/.vim/bundle
git clone https://github.com/mauritsvdvijgh/flutter-reload.vim.git

(For Neovim, change ~/.vim/ to ~/.config/nvim/.)

curl -fLo ~/.vim/plugin/reload.vim --create-dirs \
  https://raw.githubusercontent.com/mauritsvdvijgh/flutter-reload.vim/master/plugin/reload.vim
curl -fLo ~/.vim/ftplugin/dart.vim --create-dirs \
  https://raw.githubusercontent.com/mauritsvdvijgh/flutter-reload.vim/master/ftplugin/dart.vim

md ~\vimfiles\plugin
md ~\vimfiles\doc
$pluguri = 'https://raw.githubusercontent.com/mauritsvdvijgh/flutter-reload.vim/master/plugin/reload.vim'
$ftpluguri = 'https://raw.githubusercontent.com/mauritsvdvijgh/flutter-reload.vim/master/ftplugin/dart.vim'
(New-Object Net.WebClient).DownloadFile($pluguri, $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath("~\vimfiles\plugin\reload.vim"))
(New-Object Net.WebClient).DownloadFile($ftpluguri, $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath("~\vimfiles\ftplugin\dart.vim"))

In your flutter project, you will exectue flutter run (or flutter run -d {DEVICE_NAME} to specify the device you want).

NO NEED to use --pid-file to specify a pid file.

Make some changes to your project's *.dart files and you will see flutter reload automatically.

Simply sending SIGUSR1 to the flutter process in vim's BufWritePost.

(inspired from reisub0/hot-reload.vim)