Signals that a single key has possibly changed. Backend
implementations should call this if a key has possibly changed its
value.
key must be a valid key (ie starting with a slash, not containing
'//', and not ending with a slash).
The implementation must call this function during any call to
Settings.backendWrite, before the call returns (except in the
case that no keys are actually changed and it cares to detect this
fact). It may not rely on the existence of a mainloop for
dispatching the signal later.
The implementation may call this function at any other time it likes
in response to other events (such as changes occurring outside of the
program). These calls may originate from a mainloop or may originate
in response to any other action (including from calls to
Settings.backendWrite).
In the case that this call is in response to a call to
Settings.backendWrite then origin_tag must be set to the same
value that was passed to that call.
Signals that a single key has possibly changed. Backend implementations should call this if a key has possibly changed its value.
key must be a valid key (ie starting with a slash, not containing '//', and not ending with a slash).
The implementation must call this function during any call to Settings.backendWrite, before the call returns (except in the case that no keys are actually changed and it cares to detect this fact). It may not rely on the existence of a mainloop for dispatching the signal later.
The implementation may call this function at any other time it likes in response to other events (such as changes occurring outside of the program). These calls may originate from a mainloop or may originate in response to any other action (including from calls to Settings.backendWrite).
In the case that this call is in response to a call to Settings.backendWrite then origin_tag must be set to the same value that was passed to that call.