Example request that is dying:
NEW REQUEST! lightning_websocketd:main [1955685] <-- bad request from safari
read 507
write_all 1
-> websocket_to_lightningd
-> read_payload_header
read 2
read_all 1
read -11 <--- This tried to read a part of the header, is this -EAGAIN?
read_all 0 should we be blocking on these reads?
*dies*
Fixes#5089
Changelog-Fixed: `experimental-websocket` intermittent read errors fixed
Signed-off-by: William Casarin <jb55@jb55.com>