A fairly simple change: ccan/io will now call the underlying I/O
routines repeatedly until they indicate they are unfinished, *or* fail
with EAGAIN. This should make a significant difference to large
nodes, which currently spend far too much time calling poll() to
discover a single fd is still writable (mainly, for streaming gossip).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: connectd: now should use far less CPU on large nodes.
341b62eea3