WP_Filesystem_SSH2::owner

	 *
	 * @param string $file Path to the file.
	 * @return string|false Username of the owner on success, false on failure.
	 */
	public function owner( $file ) {
		$owneruid = @fileowner( $this->sftp_path( $file ) );

		if ( ! $owneruid ) {
			return false;
		}