remove unused field
verify channel handler is single threaded
Revert "verify channel handler is single threaded"

This reverts commit d67c30410489b81b4407780adad1cee877e407a5.
remove flushing thread
single threaded batching
different servers, shared client
separate clients
shared server
client: separate event loop groups
Revert "client: separate event loop groups"

This reverts commit d87890e3f93c6cff7c605faef140105404197e4d.
separate counters
cleanup
cleanup
simpler batching
fix buffer
flush after processing all i/o
optimize buffer
fix netty3 benchmark counter contention
netty3 batch writer
simple rep req benchmark