Fix #1800 - Enable non-blocking writes where available

autoload/ale/job.vim

@@ -249,6 +249,11 @@ function! ale#job#Start(command, options) abort
             let l:job_options.exit_cb = function('s:VimExitCallback')
         endif
 
+        " Use non-blocking writes for Vim versions that support the option.
+        if has('patch-8.1.350')
+            let l:job_options.noblock = 1
+        endif
+
         " Vim 8 will read the stdin from the file's buffer.
         let l:job_info.job = job_start(a:command, l:job_options)
         let l:job_id = ale#job#ParseVim8ProcessID(string(l:job_info.job))

autoload/ale/socket.vim

@@ -55,11 +55,18 @@ function! ale#socket#Open(address, options) abort
 
     if !has('nvim')
         " Vim
-        let l:channel_info.channel = ch_open(a:address, {
+        let l:channel_options = {
         \   'mode': l:mode,
         \   'waittime': 0,
         \   'callback': function('s:VimOutputCallback'),
-        \})
+        \}
+
+        " Use non-blocking writes for Vim versions that support the option.
+        if has('patch-8.1.350')
+            let l:channel_options.noblock = 1
+        endif
+
+        let l:channel_info.channel = ch_open(a:address, l:channel_options)
         let l:vim_info = ch_info(l:channel_info.channel)
         let l:channel_id = !empty(l:vim_info) ? l:vim_info.id : -1
     elseif exists('*chansend') && exists('*sockconnect')