Function initialize_session 

pub fn initialize_session(
    answer: &JsonObject,
    preferred: ProtocolVersion,
    supported: &SupportedVersions,
    config: &ClientConfig,
) -> Result<NegotiatedSession, HandshakeError>

Reads an initialize answer into a session.

The three required fields of InitializeResult and nothing else. instructions is ignored rather than carried: it is a human-facing hint with no client behaviour behind it, and a session that stored it would hand callers a field nothing gates on.

Errors

HandshakeError::MalformedResult naming the field that is wrong, and NegotiationError::UnsupportedServerVersion when the answer is a revision this build cannot speak.