private boolean doUnbind() {
			try {
				context.unbindService(this);
			} catch (final RuntimeException e) {		// IllegalArgumentException: Service not registered
				Log.e(TAG, "Failed to unbind service", e);
				return false;
			}
			return true;
		}
Delegate ServiceConnection running in target user, delivering callbacks back to the caller in originating user.
engine/src/main/java/com/oasisfeng/island/shuttle/ServiceShuttleActivity.java