Plug 'prabirshrestha/asyncomplete.vim'
Plug 'prabirshrestha/asyncomplete-buffer.vim'

call asyncomplete#register_source(asyncomplete#sources#buffer#get_source_options({
    \ 'name': 'buffer',
    \ 'allowlist': ['*'],
    \ 'blocklist': ['go'],
    \ 'completor': function('asyncomplete#sources#buffer#completor'),
    \ 'config': {
    \    'max_buffer_size': 5000000,
    \  },
    \ }))

let g:asyncomplete_buffer_clear_cache = 1