v2::V2NIMSignallingJoinParams 成员列表

成员的完整列表，这些成员属于 v2::V2NIMSignallingJoinParams,包括所有继承而来的类成员

channelId	v2::V2NIMSignallingJoinParams
rtcConfig	v2::V2NIMSignallingJoinParams
serverExtension	v2::V2NIMSignallingJoinParams
signallingConfig	v2::V2NIMSignallingJoinParams