Too many improvements and changes to list.

Will include a detailed changelog for release.

So it begins :)

Closes #172

On average, we are 1.75x faster than both now 🚀

goos: linux
goarch: amd64
pkg: nhooyr.io/websocket
Benchmark_mask/2/basic-8         	263923018	         4.55 ns/op	 439.76 MB/s
Benchmark_mask/2/nhooyr-8        	200203578	         6.00 ns/op	 333.32 MB/s
Benchmark_mask/2/gorilla-8       	241622557	         4.95 ns/op	 404.38 MB/s
Benchmark_mask/2/gobwas-8        	200392592	         6.05 ns/op	 330.69 MB/s
Benchmark_mask/3/basic-8         	207684956	         5.78 ns/op	 519.07 MB/s
Benchmark_mask/3/nhooyr-8        	169297215	         7.10 ns/op	 422.49 MB/s
Benchmark_mask/3/gorilla-8       	205775799	         5.81 ns/op	 516.23 MB/s
Benchmark_mask/3/gobwas-8        	165921662	         7.23 ns/op	 415.06 MB/s
Benchmark_mask/4/basic-8         	167034886	         7.18 ns/op	 557.30 MB/s
Benchmark_mask/4/nhooyr-8        	287656454	         4.30 ns/op	 931.11 MB/s
Benchmark_mask/4/gorilla-8       	166140434	         7.30 ns/op	 547.57 MB/s
Benchmark_mask/4/gobwas-8        	138138087	         8.73 ns/op	 458.20 MB/s
Benchmark_mask/8/basic-8         	121179904	         9.92 ns/op	 806.67 MB/s
Benchmark_mask/8/nhooyr-8        	199632992	         6.07 ns/op	1318.60 MB/s
Benchmark_mask/8/gorilla-8       	100000000	        10.8 ns/op	 739.65 MB/s
Benchmark_mask/8/gobwas-8        	157898031	         7.54 ns/op	1061.27 MB/s
Benchmark_mask/16/basic-8        	73648268	        16.5 ns/op	 971.56 MB/s
Benchmark_mask/16/nhooyr-8       	186871615	         6.38 ns/op	2506.61 MB/s
Benchmark_mask/16/gorilla-8      	72374540	        16.6 ns/op	 964.36 MB/s
Benchmark_mask/16/gobwas-8       	127698723	         9.36 ns/op	1709.99 MB/s
Benchmark_mask/32/basic-8        	40010325	        29.8 ns/op	1073.76 MB/s
Benchmark_mask/32/nhooyr-8       	168590156	         7.12 ns/op	4494.72 MB/s
Benchmark_mask/32/gorilla-8      	67282072	        17.7 ns/op	1808.59 MB/s
Benchmark_mask/32/gobwas-8       	120038877	         9.96 ns/op	3213.55 MB/s
Benchmark_mask/128/basic-8       	10134963	       118 ns/op	1082.74 MB/s
Benchmark_mask/128/nhooyr-8      	100000000	        11.8 ns/op	10852.23 MB/s
Benchmark_mask/128/gorilla-8     	45452385	        26.4 ns/op	4853.64 MB/s
Benchmark_mask/128/gobwas-8      	57188290	        20.8 ns/op	6153.80 MB/s
Benchmark_mask/512/basic-8       	 2707371	       442 ns/op	1159.38 MB/s
Benchmark_mask/512/nhooyr-8      	37049421	        32.4 ns/op	15785.82 MB/s
Benchmark_mask/512/gorilla-8     	19006171	        62.8 ns/op	8150.01 MB/s
Benchmark_mask/512/gobwas-8      	21394864	        55.8 ns/op	9169.49 MB/s
Benchmark_mask/4096/basic-8      	  346566	      3467 ns/op	1181.46 MB/s
Benchmark_mask/4096/nhooyr-8     	 5170425	       232 ns/op	17648.07 MB/s
Benchmark_mask/4096/gorilla-8    	 2963664	       405 ns/op	10105.59 MB/s
Benchmark_mask/4096/gobwas-8     	 2989596	       402 ns/op	10192.40 MB/s
Benchmark_mask/16384/basic-8     	   86671	     13833 ns/op	1184.38 MB/s
Benchmark_mask/16384/nhooyr-8    	 1332649	       889 ns/op	18436.40 MB/s
Benchmark_mask/16384/gorilla-8   	  763900	      1556 ns/op	10527.53 MB/s
Benchmark_mask/16384/gobwas-8    	  764034	      1553 ns/op	10548.60 MB/s
PASS
ok  	nhooyr.io/websocket	64.091s

Results from a 8 GB 8 core Haswell VM on GCP.

Optimize masking with math/bits

Thanks again to @renthraysk

This provides another significant speedup.

benchmark                        old MB/s     new MB/s     speedup
Benchmark_mask/2/fast-8          405.48       513.25       1.27x
Benchmark_mask/3/fast-8          518.93       661.92       1.28x
Benchmark_mask/4/fast-8          1207.10      1252.39      1.04x
Benchmark_mask/8/fast-8          1708.82      1655.63      0.97x
Benchmark_mask/16/fast-8         3418.58      3051.25      0.89x
Benchmark_mask/32/fast-8         5789.43      5813.31      1.00x
Benchmark_mask/128/fast-8        12819.53     14804.50     1.15x
Benchmark_mask/512/fast-8        18247.06     21659.50     1.19x
Benchmark_mask/4096/fast-8       19802.31     23885.68     1.21x
Benchmark_mask/16384/fast-8      20896.97     25081.11     1.20x

See https://github.com/golang/go/issues/31586#issuecomment-550040882

Thanks @renthraysk

benchmark                      old MB/s     new MB/s     speedup
BenchmarkXOR/2/fast-8          470.88       492.61       1.05x
BenchmarkXOR/3/fast-8          602.24       719.25       1.19x
BenchmarkXOR/4/fast-8          718.82       1186.64      1.65x
BenchmarkXOR/8/fast-8          1027.60      1718.71      1.67x
BenchmarkXOR/16/fast-8         1413.31      3430.46      2.43x
BenchmarkXOR/32/fast-8         2701.81      5585.42      2.07x
BenchmarkXOR/128/fast-8        7757.97      13432.37     1.73x
BenchmarkXOR/512/fast-8        15155.03     18797.79     1.24x
BenchmarkXOR/4096/fast-8       20689.95     20334.61     0.98x
BenchmarkXOR/16384/fast-8      21687.87     21613.94     1.00x

Now its faster than basic XOR at every byte size greater than 2 on
little endian amd64 machines.

Fix race with c.readerShouldLock

Closes #168

CODEOWNERS is unnecessary.

Fix concurrent read with close

Closes #164

Switch to coveralls.io from codecov.io

No need to test both client and server side.

codecov's uploader keeps failing due to the API being unresponsive and the UI is cluttered
compared to codecov.

- For JS we ensure we indicate which size initiated the close first from our POV
- For normal Go, concurrent closes block until the first one succeeds instead of returning early