unexpected behavior about passMessageObject with nil messageObject.

[simpzan]

- (void)passMessageObject:(nullable id <NSCoding>)messageObject identifier:(nullable NSString *)identifier
when this api is called with nil messageObject parameter, it will not remove the existing message, causing the other side receive the stale data, instead of nil data. Is this an expected behavior?

related code logic is here https://github.com/mutualmobile/MMWormhole/blob/master/Source/MMWormholeFileTransiting.m#L105-L118