Updates the event mask to watch for the fd identified by tag.
tag is the tag returned from add_unix_fd.
If you want to remove a fd, don't set its event mask to zero. Instead, call remove_unix_fd.
This API is only intended to be used by implementations of SocketSource. Do not call this API on a SocketSource that you did not create.
As the name suggests, this function is not available on Windows.
| this | |
| tag |
the tag from add_unix_fd |
| new_events |
the new event mask to watch |