When using Bitmessage, everybody receives all the messages in the blockchain. How is the timing attack going to identify him? Maybe Bitmessage helps receiving

When using Bitmessage, everybody receives all the messages in the blockchain. How is the timing attack going to identify him? Maybe Bitmessage helps receiving messages anonymously, but the timing attack might still be possible when sending messages. I2P can mitigate the problem, but I don't think Bitmessage has any nodes in I2P. I would say that, if you don't trust Poulsen, don't talk to him.