This method should acquire an exclusive lock on the resource that is about to be used to read and write the session data.
The lock should only be released in the close method.
Note that this will effectively serialize parallel requests, which affects performance for a single user session.
Not locking the resource would on the other hand allow for race conditions if two or more parallel requests change the session data.
(PHP 5 >= 5.4.0)
SessionHandlerInterface::open — Initialize session
Re-initialize existing session, or creates a new one. Called when a session starts or when session_start() is invoked.
The path where to store/retrieve the session.
The session name.
The return value (usually
TRUE on success,
FALSE on failure). Note this value is returned internally to PHP for processing.