protected function connect(UriInterface $uri, $timeout = null)
	{
		$errno = null;
		$err = null;

		// Get the host from the uri.
		$host = ($uri->isSSL()) ? 'ssl://' . $uri->getHost() : $uri->getHost();

		// If the port is not explicitly set in the URI detect it.
		if (!$uri->getPort())
		{
			$port = ($uri->getScheme() == 'https') ? 443 : 80;
		}

		// Use the set port.
		else
		{
			$port = $uri->getPort();
		}

		// Build the connection key for resource memory caching.
		$key = md5($host . $port);

		// If the connection already exists, use it.
		if (!empty($this->connections[$key]) && is_resource($this->connections[$key]))
		{
			// Connection reached EOF, cannot be used anymore
			$meta = stream_get_meta_data($this->connections[$key]);

			if ($meta['eof'])
			{
				if (!fclose($this->connections[$key]))
				{
					throw new \RuntimeException('Cannot close connection');
				}
			}

			// Make sure the connection has not timed out.
			elseif (!$meta['timed_out'])
			{
				return $this->connections[$key];
			}
		}

		if (!is_numeric($timeout))
		{
			$timeout = ini_get('default_socket_timeout');
		}

		// Capture PHP errors
		$php_errormsg = '';
		$track_errors = ini_get('track_errors');
		ini_set('track_errors', true);

		// PHP sends a warning if the uri does not exists; we silence it and throw an exception instead.
		// Attempt to connect to the server
		$connection = @fsockopen($host, $port, $errno, $err, $timeout);

		if (!$connection)
		{
			if (!$php_errormsg)
			{
				// Error but nothing from php? Create our own
				$php_errormsg = sprintf('Could not connect to resource: %s', $uri, $err, $errno);
			}

			// Restore error tracking to give control to the exception handler
			ini_set('track_errors', $track_errors);

			throw new \RuntimeException($php_errormsg);
		}

		// Restore error tracking to what it was before.
		ini_set('track_errors', $track_errors);

		// Since the connection was successful let's store it in case we need to use it later.
		$this->connections[$key] = $connection;

		// If an explicit timeout is set, set it.
		if (isset($timeout))
		{
			stream_set_timeout($this->connections[$key], (int) $timeout);
		}

		return $this->connections[$key];
	}