[Feature request] Asynchronous GoToReferences

[zeminzhou]

Issue Prelude

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• If filing a bug report, I have included the output of vim --version.
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  my issue, using vim -Nu /path/to/YCM/vimrc_ycm_minimal, including what I
  expected to happen and what actually happened.
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Issue Details

Provide a clear description of the problem, including the following key
questions:

• What did you do?
  Generally, vim stuck for a while when I call GoToReferences in go project(because the project is large).
  So I want to know if there is a way to make vim not stuck for a while (meaning I can still move the cursor) when I call GoToReferences.
  Thanks!

Include steps to reproduce here.

1. vim -Nu /path/to/YCM/ycm_vimrc_minimal
2. :edit test.py
3. Enter insert mode and type .....

Include description of a minimal test case, including any actual code required
to reproduce the issue.

If you made changes to vimrc_ycm_minimal, pase them here:

" YCM
let g:ycm_autoclose_preview_window_after_insertion = 1
let g:ycm_enable_inlay_hints = 0
let g:ycm_update_diagnostics_in_insert_mode = 1
let g:ycm_show_detailed_diag_in_popup = 1
let g:ycm_global_ycm_extra_conf = '/root/.ycm_extra_conf.py'
let g:ycm_autoclose_preview_window_after_completion = 1
let g:ycm_show_diagnostics_ui = 1
let g:ycm_error_symbol = 'xx'
let g:ycm_warning_symbol = '>>'
let g:ycm_collect_identifiers_from_tags_files = 1
let g:ycm_key_detailed_diagnostics = '<leader>ym'
let g:ycm_add_preview_to_completeopt = 'popup'
let g:ycm_enable_semantic_highlighting = 1
let g:ycm_seed_identifiers_with_syntax=0
let g:ycm_complete_in_comments=1
let g:ycm_complete_in_strings=1
nnoremap <leader>yw <Plug>(YCMFindSymbolInWorkspace)
nnoremap <silent> <leader>yc :YcmCompleter GoToDeclaration<CR>
nnoremap <silent> <leader>yd :YcmCompleter GoToDefinition<CR>
nnoremap <silent> <leader>ys :YcmCompleter GoToSymbol <C-R><C-W><CR>
nnoremap <silent> <leader>yi :YcmCompleter GoToImplementation<CR>
nnoremap <silent> <leader>yr :YcmCompleter GoToReferences<CR>
nnoremap <silent> <leader>yf :YcmCompleter GoToInclude<CR>
nnoremap <silent> <leader>ye :YcmDiags<CR>
nnoremap <silent> <leader>yt :let g:ycm_auto_trigger = g:ycm_auto_trigger == 1 ? 0 : 1<CR>
let g:ycm_language_server =
  \ [
  \   {
  \     'name': 'rust',
  \     'cmdline': [ '/Users/zzm/.local/bin/rust-analyzer' ],
  \     'filetypes': [ 'rust' ],
  \     'project_root_files': [ 'Cargo.toml' ]
  \   },
  \   {
  \     'name': 'go',
  \     'cmdline': [ '/Users/zzm/go/bin/gopls' ],
  \     'filetypes': [ 'go' ],
  \     'project_root_files': [ 'go.mod' ]
  \   },
  \ ]

• What did you expect to happen?

Include description of the expected behaviour.

• What actually happened?

Include description of the observed behaviour, including actual output,
screenshots, etc.

Diagnostic data

Output of vim --version

VIM - Vi IMproved 9.0 (2022 Jun 28, compiled Oct 08 2022 18:26:41)
macOS version - arm64
Included patches: 1-700
Compiled by Homebrew

Output of YcmDebugInfo

Paste output here

Output of YcmDiags

Paste output here

Output of git rev-parse HEAD in YouCompleteMe installation directory

paste output here

Contents of YCM, ycmd and completion engine logfiles

Reproduce the issue with vim -Nu /path/to/YCM/vimrc_ycm_minimal, which
enabled debug logging and other useful diagnostics. Include a link to a
gist containing all of the log files listed by :YcmToggleLogs.

OS version, distribution, etc.

Include system information here.

Output of build/install commands

Include link to a gist containing the invocation and entire output of
install.py if reporting an installation issue.

[bstaletic]

Needs more testing, but I have this implemented here: https://github.com/bstaletic/YouCompleteMe/tree/async-commands