00000210  30 33 cf 04 16 03 03 00  04 0e 00 00 00           |03...........|
>>> Flow 3 (client to server)
00000000  16 03 03 00 25 10 00 00  21 20 2f e5 7d a3 47 cd  |....%...! /.}.G.|
00000010  62 43 15 28 da ac 5f bb  29 07 30 ff f6 84 af c4  |bC.(.._.).0.....|
00000020  cf c2 ed 90 99 5f 58 cb  3b 74 14 03 03 00 01 01  |....._X.;t......|
00000030  16 03 03 00 20 69 ac be  cf f1 3d 8a 4e f3 3a 54  |.... i....=.N.:T|

	// Helper to read a single counter data file.
	readcdf := func(cdf string) error {
		cf, err := os.Open(cdf)
		if err != nil {
			return fmt.Errorf("opening counter data file %s: %s", cdf, err)
		}
		defer cf.Close()
		var cdr *decodecounter.CounterDataReader
		cdr, err = decodecounter.NewCounterDataReader(cdf, cf)
		if err != nil {
			return fmt.Errorf("reading counter data file %s: %s", cdf, err)
		}

00000280  39 7e 17 d8 74 ae 05 a3  f5 3a 71 74 e8 b4 c9 a4  |9~..t....:qt....|
00000290  1c 82 04 ca fe 5f 97 23  8a c1 f9 ce d1 5d 0e 81  |....._.#.....]..|
000002a0  da 5f e1 b6 76 80 3c cf  9f 19 79 cf 33 d0 0a fe  |._..v.<...y.3...|
000002b0  19 fc 2d 9a bb 24 cd d4  79 14 03 03 00 01 01 16  |..-..$..y.......|
000002c0  03 03 00 28 00 00 00 00  00 00 00 00 28 78 b8 0b  |...(........(x..|

00000100  28 da ac 5f bb 29 07 30  ff f6 84 af c4 cf c2 ed  |(.._.).0........|
00000110  90 99 5f 58 cb 3b 74                              |.._X.;t|
>>> Flow 2 (server to client)
00000000  16 03 03 00 7a 02 00 00  76 03 03 c2 2e 95 0c cf  |....z...v.......|
00000010  63 40 d8 a0 bd 51 27 e2  62 79 72 26 b1 d4 38 5b  |c@...Q'.byr&..8[|
00000020  50 03 66 d2 2e 8e 46 b7  cf 40 0a 20 00 00 00 00  |P.f...F..@. ....|

000000e0  1d 00 20 2f e5 7d a3 47  cd 62 43 15 28 da ac 5f  |.. /.}.G.bC.(.._|
000000f0  bb 29 07 30 ff f6 84 af  c4 cf c2 ed 90 99 5f 58  |.).0.........._X|
00000100  cb 3b 74                                          |.;t|
>>> Flow 2 (server to client)
00000000  16 03 03 00 7a 02 00 00  76 03 03 24 80 76 3d db  |....z...v..$.v=.|
00000010  cf 32 53 04 de ce 2e 74  95 bb 30 a8 d5 5e ab ed  |.2S....t..0..^..|

000000f0  bb 29 07 30 ff f6 84 af  c4 cf c2 ed 90 99 5f 58  |.).0.........._X|
00000100  cb 3b 74                                          |.;t|
>>> Flow 2 (server to client)
00000000  16 03 03 01 ca 02 00 01  c6 03 03 da b0 57 a0 ee  |.............W..|
00000010  bf 74 92 06 39 a6 9a 9b  80 71 7e 57 63 ab 31 74  |.t..9....q~Wc.1t|
00000020  d3 22 c1 e3 a6 c6 cf 6f  47 57 49 20 86 52 fb 0a  |.".....oGWI .R..|

00000150  a1 73 68 fb 87 2c 9d d2  d3 cf d7 3a bb 36 7e 83  |.sh..,.....:.6~.|
00000160  c3 3f bc e2 61 d9 c2 8b  15 a2 cc bf 14 a0 69 f4  |.?..a.........i.|
00000170  22 02 a9 ff 5e 55 37 6e  61 86 71 73 94 2f 7e 50  |"...^U7na.qs./~P|
00000180  45 96 cf 23 dd 39 90 5d  57 04 a3 d0 9f 97 f8 56  |E..#.9.]W......V|
00000190  fa cf 7a a9 e6 57 1f cb  33 a0 82 7a 84 94 1f 6d  |..z..W..3..z...m|

000000f0  bb 29 07 30 ff f6 84 af  c4 cf c2 ed 90 99 5f 58  |.).0.........._X|
00000100  cb 3b 74                                          |.;t|
>>> Flow 2 (server to client)
00000000  16 03 01 00 5d 02 00 00  59 03 01 24 71 03 c6 1d  |....]...Y..$q...|
00000010  d4 f5 09 b2 3c d8 88 51  57 4c 90 07 4b 74 fe 1d  |....<..QWL..Kt..|
00000020  c9 7f 00 78 9b a3 b2 1b  ef 43 66 20 07 97 7c a6  |...x.....Cf ..|.|

000000d0  08 03 04 03 03 03 02 03  01 00 33 00 26 00 24 00  |..........3.&.$.|
000000e0  1d 00 20 2f e5 7d a3 47  cd 62 43 15 28 da ac 5f  |.. /.}.G.bC.(.._|
000000f0  bb 29 07 30 ff f6 84 af  c4 cf c2 ed 90 99 5f 58  |.).0.........._X|
00000100  cb 3b 74                                          |.;t|
>>> Flow 2 (server to client)
00000000  16 03 01 00 5d 02 00 00  59 03 01 5a a9 a1 6f fa  |....]...Y..Z..o.|

func BatchedEventFilter[I, O any](cf func(a I) O, handler func(events []Event[I], initialSync bool)) func(o []Event[I], initialSync bool) {
	return func(events []Event[I], initialSync bool) {
		ev := slices.FilterInPlace(events, func(e Event[I]) bool {
			if e.Old != nil && e.New != nil {
				if equal(cf(*e.Old), cf(*e.New)) {
					// Equal under conversion, so we can skip
					return false
				}