Function initialize_params 

pub fn initialize_params(
    preferred: ProtocolVersion,
    config: &ClientConfig,
) -> Result<JsonObject, HandshakeError>

The initialize params: the offer, what this client can do, and who it is.

The three required fields of InitializeRequest. The capabilities are rendered from the client’s own set rather than passed in as a Value, so there is no way to advertise a capability the profile behind it would refuse.

Errors

HandshakeError::Assembling if the params do not serialise, which for this input cannot happen — a map of strings and booleans always does.