sliices are only too slow if there's something pending

logging mods
i really need to rewrite the tcp transport - the code is all functional, but the design sucks.
with the FIFO bandwidth limiter we could get away with a single 'send' thread rather than each TCPConnection having its own writer thread (but we'd still need the per-con reader thread, at least until nio is solid enough)
but maybe the rewrite can hold off until the AMOC implementation.  we'll see