Add OmniSharp extension to display server status

autoload/airline/extensions/omnisharp.vim

@@ -0,0 +1,45 @@
+" MIT License
+" Plugin: https://github.com/OmniSharp/omnisharp-vim
+" vim: et ts=2 sts=2 sw=2
+
+scriptencoding utf-8
+
+if !get(g:, 'OmniSharp_loaded', 0)
+  finish
+endif
+
+function! airline#extensions#omnisharp#server_status(...) abort
+  if !exists(':OmniSharpGotoDefinition') || !get(g:, 'OmniSharp_server_stdio', 0)
+    return ''
+  endif
+
+  let host = OmniSharp#GetHost(bufnr('%'))
+  if type(host.job) != v:t_dict || get(host.job, 'stopped')
+    return ''
+  endif
+
+  let sln = fnamemodify(host.sln_or_dir, ':t')
+
+  if get(host.job, 'loaded', 0)
+    return sln
+  endif
+
+  try
+    let projectsloaded = OmniSharp#project#CountLoaded()
+    let projectstotal = OmniSharp#project#CountTotal()
+  catch
+    " The CountLoaded and CountTotal functions are very new - catch the error
+    " when they don't exist
+    let projectsloaded = 0
+    let projectstotal = 0
+  endtry
+  return printf('%s(%d/%d)', sln, projectsloaded, projectstotal)
+endfunction
+
+function! airline#extensions#omnisharp#init(ext) abort
+  call airline#parts#define_function('omnisharp', 'airline#extensions#omnisharp#server_status')
+  augroup airline_omnisharp
+    autocmd!
+    autocmd User OmniSharpStarted,OmniSharpReady,OmniSharpStopped AirlineRefresh!
+  augroup END
+endfunction