Abstract base for requests, which includes common info in all requests.
| accessTokenString | The JSON encoded binary access token this client uses to authenticate its session for future commands. |
| appId | AppID for the current game, required in every request. This is generated from the Cloud API. |
| domain | Domain for the request. All commands will be sandboxed to their own domain; For example no clients with domain 1 will see matches with domain 2. This can be used to prevent incompatible client versions from communicating. |
| projectId | The Cloud Project Id for this game, required in every request. This is used to match games of the same type. |
| sourceId | SourceID for the current client, required in every request. This is generated from the Cloud API. |
| version | Matchmaker protocol version info. |