Enable TCP_NODELAY, alternative approach

[edsko]

This replaces #181, and depends on

• Compatibility with http2-tls kazu-yamamoto/network-run#9 (into https://github.com/kazu-yamamoto/network-run/tree/main2) (an alternative to Add functions to accept socket options kazu-yamamoto/network-run#8)
• Compatibility with network-run kazu-yamamoto/http2-tls#17 (into https://github.com/kazu-yamamoto/http2-tls/tree/main2) (an alternative to Add settingsOpenClientSocket kazu-yamamoto/http2-tls#16)

Just to verify that we can set TCP_NODELAY both server-side and client-side, as well as with and without TLS, I did some measurements:

secure	server TCP_NODELAY	client TCP_NODELAY	performance
no	no	no	11.717 RPCs/s
no	no	yes	22.517 RPCs/s
no	yes	no	21.683 RPCs/s
no	yes	yes	1735.617 RPCs/s ✔️
--	--	--	--
yes	no	no	11.417 RPCs/s
yes	no	yes	22.983 RPCs/s
yes	yes	no	21.383 RPCs/s
yes	yes	yes	973.000 RPCs/s ✔️

(all with --no-work-simulation)

[edsko]

This now depends on

• implementing openTCPServerSocketWithOptions to not forget "listen" kazu-yamamoto/network-run#11
• Expose client socket kazu-yamamoto/http2-tls#19

[edsko]

Verified that if we don't set TCP_NODELAY on the server socket, but do set it on the client socket (from accept), we still get the expected performance, both with and without TLS, confirming that the second commit on this PR does what it's intended to do.

Tests fail however, not yet sure why, seems related to #156 .

[edsko]

Closing this in favour of #183 , which includes the changes here.