(PHP 5 >= 5.4.0, PHP 7)
SessionHandler::write — Write session data
$session_id
, string $session_data
) : boolWrites the session data to the session storage. Called by normal PHP shutdown, by session_write_close(), or when session_register_shutdown() fails. PHP will call SessionHandler::close() immediately after this method returns.
This method wraps the internal PHP save handler defined in the session.save_handler ini setting that was set before this handler was set by session_set_save_handler().
If this class is extended by inheritiance, calling the parent write method will invoke the
wrapper for this method and therefor invoke the associated internal callback. This allows this method to be
overidden and or intercepted and filtered (for example, encrypting the $data value
before sending it to the parent write method).
For more information on what this method is expected to do, please refer to the documentation at SessionHandlerInterface::write().
session_idThe session id.
session_dataThe encoded session data. This data is the result of the PHP internally encoding the $_SESSION superglobal to a serialized string and passing it as this parameter. Please note sessions use an alternative serialization method.
会话存储的返回值（通常成功返回 0，失败返回 1）。