Proposal 1: API clients want a deterministic way to wait until "all input since now" has been processed.

1. new API function e.g. nvim_input_flush() ?
2. the function generates a new token and puts it in the input queue: API: nvim_input returns a "ticket" which can be used to confirm when the input is processed #30760
   • the token is a pseudokey like <id:xxx> where xxx is a monotonic integer
3. nvim_input_flush() blocks until the token is seen by os_inchar

Proposal 2 (alternative/additionally?): API clients want to know when specific input has been processed.

1. new API function nvim_input2({keys}, {callback}): API: nvim_input returns a "ticket" which can be used to confirm when the input is processed #30760
2. same as (2) in Proposal 2.
3. When os_inchar sees a token it
   • invokes registered callbacks
   • emits nvim_input_event({token})

Reference:

• [RFC] api: nvim_get_mode() #6247
• paste: redesign, fixes, 10x speedup #4448 (comment)
• paste: redesign, fixes, 10x speedup #4448 (comment)