Performs the action associated with the command using the information in an invocation.
- macOS 10.12+
The invocation of the command to be invoked.
A block to be executed when the command finishes.
Xcode passes the code a completion handler that it must invoke to finish performing the command, passing
nil on success or an error on failure. A canceled command must still call the completion handler, passing
There are no guarantees about the thread or queue on which the cancellation handler is invoked.