Is it possible to insert completions without opening the pop-up menu?

Apologies if I've missed some documentation somewhere. I've spent a bit of time combing through issues with every search term I could think of and didn't turn anything up.

The behavior I'm after is to:

Have a relatively long delay (let's say 1s) by default for the popup to show
But when <Tab> is pressed, immediately
a. Insert the completion when only a single completion is available (with no popup shown)
b. Insert the common substring across all completions and show the completion popup when multiple completions are available

In the README, there is a key mapping listed for mapping <Tab> to show the popup, but it would be nice if it was extended to also insert a completion or substring of the completions. As well, if a long pop-up delay is set, the mapping in the README still waits for the duration of the delay before showing the popup, meaning that it's only really all that useful when auto-popup is disabled and the delay is 0.

asyncomplete.vim/README.md

Lines 44 to 60 in 2107094

    
           You can use the above `<Plug>(asyncomplete_force_refresh)` to show the popup 
        
           or can you tab to show the autocomplete. 
        
           ```vim 
        
           let g:asyncomplete_auto_popup = 0 
        
           function! s:check_back_space() abort 
        
               let col = col('.') - 1 
        
               return !col || getline('.')[col - 1]  =~ '\s' 
        
           endfunction 
        
           inoremap <silent><expr> <TAB> 
        
             \ pumvisible() ? "\<C-n>" : 
        
             \ <SID>check_back_space() ? "\<TAB>" : 
        
             \ asyncomplete#force_refresh() 
        
           inoremap <expr><S-TAB> pumvisible() ? "\<C-p>" : "\<C-h>" 
        
           ```

I don't mind doing some customization to get this configured to my liking, but I'm having trouble getting started. I couldn't find a way to access and insert completions without opening the popup menu. Any pointers for functions that I should consider, or limitations that I would have to work around would be much appreciated.

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

	You can use the above `<Plug>(asyncomplete_force_refresh)` to show the popup
	or can you tab to show the autocomplete.

	```vim
	let g:asyncomplete_auto_popup = 0

	function! s:check_back_space() abort
	let col = col('.') - 1
	return !col \|\| getline('.')[col - 1] =~ '\s'
	endfunction

	inoremap <silent><expr> <TAB>
	\ pumvisible() ? "\<C-n>" :
	\ <SID>check_back_space() ? "\<TAB>" :
	\ asyncomplete#force_refresh()
	inoremap <expr><S-TAB> pumvisible() ? "\<C-p>" : "\<C-h>"
	```