Deletes file.
If file is a directory, its contents are deleted recursively before file itself is deleted. The recursive
delete operation will stop on the first error.
If cancellable is not null, then the operation can be cancelled by triggering the
cancellable object from another thread. If the operation was cancelled, the error
CANCELLED will be returned.
| file |
a File to delete |
| cancellable |
optional Cancellable object, or null |
|
true if the file was deleted, false otherwise |