o Major bugfixes (netflow padding):
    - Stop adding unneeded channel padding right after we finish flushing
      to a connection that has been trying to flush for many seconds.
      Instead, treat all partial or complete flushes as activity on the
      channel, which will defer the time until we need to add padding.
      This fix should resolve confusing and scary log messages like
      "Channel padding timeout scheduled 221453ms in the past." Fixes
      bug 22212; bugfix on 0.3.1.1-alpha.