Simulate packet loss

I've given this some thought and I don't think that dropping bytes is a useful feature, as it does not simulate real world poor network conditions. If a packet is not received, another attempt to send it occurs, since TCP is supposed to be a guaranteed reliable delivery, with all bytes sent and in the correct order.

What really should happen is that there is a chance that a entire packet may be lost. It has to pretend to send a packet and then retransmit with the actual payload.

At the very least, dropping bytes should be a deprecated or removed feature. It seems to be highly problematic, especially if for example I am downloading a JS file and there are bytes missing, code won't execute or fuck up in unpredictable ways.

Perhaps I can attempt a PR on this.