Revert "sleep if the next message is incomplete"

This reverts commit 955e84fbd43d57dd875fcc8ae14798719f70a11f.
Revert "parentheses to clarify the order of operations"

This reverts commit 3575d6faa78d173f6e2d9076c94c0b3b8fc8936e.
Revert "sleep if the send buffer is full"

This reverts commit 987af51199c77e8ba32d6971dfa83b35397f9687.
Revert "dont process the next message if we still have getdata requests queued"

This reverts commit 5a58ca3402de332470ed38ac6d12564c0af2673b.
Revert "process one block per cycle to make resource allocation fair between peers"

This reverts commit 1c5dac9a7d86bff268fa53ff455b545012986f87.
Revert "process received messages one at a time without sleeping between messages"

This reverts commit 9e7558e04d0d81ade2def4bdb2db29b9a327c40d.
process received messages one at a time without sleeping between messages