docs: private boolean write(Pipe pipe, Msg msg)
      {
          if (!pipe.write(msg)) {
              Collections.swap(pipes, pipes.indexOf(pipe), matching - 1);
              matching--;
              Collections.swap(pipes, pipes.indexOf(pipe), active - 1);
              active--;
              Collections.swap(pipes, active, eligible - 1);
              eligible--;
              return false;
          }
          if (!msg.hasMore()) {
              pipe.flush();
          }
          return true;
      }