>>> Flow 1 (client to server)
00000000  16 03 01 00 39 01 00 00  35 03 01 96 f7 15 21 fc  |....9...5.....!.|
00000010  31 f5 cf cf e9 82 0f 84  db 34 a8 e4 3c e9 39 b4  |1........4..<.9.|
00000020  90 af d7 47 2b b5 71 8a  bb 26 b5 00 00 04 00 2f  |...G+.q..&...../|
00000030  00 ff 01 00 00 08 00 16  00 00 00 17 00 00        |..............|
>>> Flow 2 (server to client)
00000000  16 03 01 00 35 02 00 00  31 03 01 00 00 00 00 00  |....5...1.......|

00000030  cb 2c a2 05 19 6b 65 64  9b 71 2b d3 d2 19 cb 66  |.,...ked.q+....f|
00000040  61 c1 6f 19 b4 7a 15 41  76 14 85 fc c0 27 00 00  |a.o..z.Av....'..|
00000050  11 ff 01 00 01 00 00 0b  00 04 03 00 01 02 00 17  |................|
00000060  00 00 16 03 03 02 59 0b  00 02 55 00 02 52 00 02  |......Y...U..R..|
00000070  4f 30 82 02 4b 30 82 01  b4 a0 03 02 01 02 02 09  |O0..K0..........|

000000f0  0f d0 ec dd d4 75 57 0d  3f 7e a3 a4 40 f7 67 d2  |.....uW.?~..@.g.|
00000100  22 ba 5f a1 38 0b ea 8e  7d 95 43 70 52 0f b0 5f  |"._.8...}.CpR.._|
00000110  ef 26 5a 52 a6 94 b4 69  89 e9 0e 4f f5 d8 60 1b  |.&ZR...i...O..`.|
00000120  d3 6a fd 74 8d 19 ce 6a  72 f1 c1 96 f9 86 66 3b  |.j.t...jr.....f;|
00000130  2b 38 b3 e3 76 4b fd 4a  82 3e f2 2c bc 4c 19 d7  |+8..vK.J.>.,.L..|

00000070  ff f6 84 af c4 cf c2 ed  90 99 5f 58 cb 3b 74 14  |.........._X.;t.|
00000080  03 03 00 01 01 17 03 03  00 17 ce 73 37 c4 06 32  |...........s7..2|
00000090  74 c4 3d 2d 55 10 b4 ce  3f 66 fa ec 9a 8c d1 4a  |t.=-U...?f.....J|
000000a0  cd 17 03 03 02 6d 6a 73  5d 98 e7 fc 37 d2 b8 5d  |.....mjs]...7..]|
000000b0  2a 1c 75 80 b3 a9 ce 6e  e2 d0 b5 5c 70 2b e5 c0  |*.u....n...\p+..|

00000100  cb 3b 74                                          |.;t|
>>> Flow 2 (server to client)
00000000  16 03 03 00 5d 02 00 00  59 03 03 68 ad d5 4c 88  |....]...Y..h..L.|
00000010  60 b8 3b b4 ea e4 f2 55  7d 0f 90 d8 bd 55 b5 53  |`.;....U}....U.S|
00000020  49 6e f7 50 e4 05 70 a2  6d 9e a5 20 d1 0a e5 58  |In.P..p.m.. ...X|
00000030  38 f1 82 94 a7 c3 bf 77  60 d8 51 c2 c7 e9 8e d6  |8......w`.Q.....|

00000030  09 ff 01 00 01 00 00 17  00 00 16 03 03 02 59 0b  |..............Y.|
00000040  00 02 55 00 02 52 00 02  4f 30 82 02 4b 30 82 01  |..U..R..O0..K0..|
00000050  b4 a0 03 02 01 02 02 09  00 e8 f0 9d 3f e2 5b ea  |............?.[.|
00000060  a6 30 0d 06 09 2a 86 48  86 f7 0d 01 01 0b 05 00  |.0...*.H........|
00000070  30 1f 31 0b 30 09 06 03  55 04 0a 13 02 47 6f 31  |0.1.0...U....Go1|

00000030  09 ff 01 00 01 00 00 17  00 00 16 03 03 02 59 0b  |..............Y.|
00000040  00 02 55 00 02 52 00 02  4f 30 82 02 4b 30 82 01  |..U..R..O0..K0..|
00000050  b4 a0 03 02 01 02 02 09  00 e8 f0 9d 3f e2 5b ea  |............?.[.|
00000060  a6 30 0d 06 09 2a 86 48  86 f7 0d 01 01 0b 05 00  |.0...*.H........|
00000070  30 1f 31 0b 30 09 06 03  55 04 0a 13 02 47 6f 31  |0.1.0...U....Go1|

// If a and b are different IP versions, 0 is returned.
//
// See https://tools.ietf.org/html/rfc6724#section-2.2
func commonPrefixLen(a netip.Addr, b IP) (cpl int) {
	if b4 := b.To4(); b4 != nil {
		b = b4
	}
	aAsSlice := a.AsSlice()
	if len(aAsSlice) != len(b) {
		return 0
	}
	// If IPv6, only up to the prefix (first 64 bits)
	if len(aAsSlice) > 8 {
		aAsSlice = aAsSlice[:8]

00000030  09 ff 01 00 01 00 00 17  00 00 16 03 03 02 59 0b  |..............Y.|
00000040  00 02 55 00 02 52 00 02  4f 30 82 02 4b 30 82 01  |..U..R..O0..K0..|
00000050  b4 a0 03 02 01 02 02 09  00 e8 f0 9d 3f e2 5b ea  |............?.[.|
00000060  a6 30 0d 06 09 2a 86 48  86 f7 0d 01 01 0b 05 00  |.0...*.H........|
00000070  30 1f 31 0b 30 09 06 03  55 04 0a 13 02 47 6f 31  |0.1.0...U....Go1|

00000030  09 ff 01 00 01 00 00 17  00 00 16 03 03 02 59 0b  |..............Y.|
00000040  00 02 55 00 02 52 00 02  4f 30 82 02 4b 30 82 01  |..U..R..O0..K0..|
00000050  b4 a0 03 02 01 02 02 09  00 e8 f0 9d 3f e2 5b ea  |............?.[.|
00000060  a6 30 0d 06 09 2a 86 48  86 f7 0d 01 01 0b 05 00  |.0...*.H........|
00000070  30 1f 31 0b 30 09 06 03  55 04 0a 13 02 47 6f 31  |0.1.0...U....Go1|