Since the streambuf instance will be invalidated by anything written to
it while it's being sent using an async call we need to use multiple
streambuf instances.
Since we're targetting the latest LTS release of Ubuntu as a nice
baseline, and that currently only supports 1.46, we need to remove the
nice steady_timer code. For now.
This commit should probably be reverted once a newer version of Ubuntu
LTS is available.