Within the macdrv WINE_IME_POST_UPDATE code path, there are no message post/send operations
We still need `NtUserMsgWaitForMultipleObjectsEx` to drain the driver events though, since that is the mechanism by which `macdrv_sent_text_input` eventually gets called (which still happens here and would break if replaced by `NtWaitForSingleObject`).
Creating an NT event just for this purpose seems a bit overkill IMO, there is really no reason this call to `macdrv_ime_process_key` needs to be asynchronous with the current design in the first place.