Currently, kbx/backend-sqlite.c uses three phase setup for info_cb with dotlock_create, dotlock_set_info_cb and dotlock_finish_create .
This can be done by a single step, say, with dotlock_create_with, supplying the call back function.
And, we can change the semantics of call back function to be responsible to all about emitting message.
(Current use case: info_cb could only handle a specific reason; kbx/backend-sqlite.c only handles DOTLOCK_WAITING, leaving other reasons to the dotlock implementation.)