WP_Filesystem_SSH2::delete( string $file, bool $recursive = false, string|bool $type = false )

	public function delete($file, $recursive = false, $type = false) {
		if ( 'f' == $type || $this->is_file($file) )
			return ssh2_sftp_unlink($this->sftp_link, $file);
		if ( ! $recursive )
			 return ssh2_sftp_rmdir($this->sftp_link, $file);
		$filelist = $this->dirlist($file);
		if ( is_array($filelist) ) {
			foreach ( $filelist as $filename => $fileinfo) {
				$this->delete($file . '/' . $filename, $recursive, $fileinfo['type']);
			}
		}
		return ssh2_sftp_rmdir($this->sftp_link, $file);
	}