用于被叫方的呼叫邀请内容

@property (nonatomic, copy, nonnull, readonly) NSString *callerId;

@property (nonatomic, copy, nullable, readonly) NSString *content;

@property (nonatomic, copy, nullable) NSString *response;

@property (nonatomic, copy, nullable, readonly) NSString *channelId;

@property (nonatomic, assign, readonly) ARtmRemoteInvitationState state;