#http\Client http\Client::attach(SplObserver $observer)

Implements SplSubject. Attach another observer. Attached observers will be notified with progress of each transfer.

Params:#

• SplObserver $observer#
  An implementation of SplObserver.

Returns:#

• http\Client, self.

Throws:#

• http\Exception\InvalidArgumentException
• http\Exception\UnexpectedValueException