3.2.5.2 Exclusive Get Requests
A client that uses a state server makes either an exclusive or a non-exclusive request to a state server implementation for session state data.<14>
For an exclusive request, the client sends an HTTP request by using the message format that is specified in section 2.2.5.3.
If the server responds with a response-ok message, as specified in section 2.2.5.4, the client MUST perform implementation-specific initialization tasks if the server returns an action-flags value of "1". The client MUST retain the value of the lock-cookie field. If the client needs to update the session state data, it MUST send the same lock-cookie value back to the state server as part of a Set_Request message. When the client no longer requires an exclusive lock on the session state data, it MUST send the same lock-cookie value back to the state server. This occurs when the client releases its lock with a ReleaseExclusive_Request message.
If the server responds with a response-locked message, as specified in section 2.2.5.4, the client MAY retain the lock-cookie, lock-age, and lock-date values for use with custom concurrency handling.<15>
If the server responds with either a response-bad-request or a response-not-found message, as specified in section 2.2.5.4, the client MAY surface some type of error back to the client's caller.<16>