shibox/fastblockcopy

Copy is optimized for small data,such as 32 bytes. in 32 bytes it can 2.5x than Buffer.BlockCopy(),in 200 bytes,it fast than 2x,in 1024 bytes,it fast than 1.25x,in any case,it fast!

FastBlockCopy

Copy is optimized for small data,such as 32 bytes. in 32 bytes it can 1.5x than Buffer.BlockCopy(),in 100 bytes,it fast than 1.2x,is is more,use Buffer.BlockCopy(),is fast.

use:

1 FastBuffer.UnsafeBlockCopy(from, 0, to, 0, 100); without bounds checking,also it more fast

2 FastBuffer.BlockCopy(from, 0, to, 0, 100); with bounds checking

and it also can use:from.UnsafeBlockCopy(0, to, 0, 100)

但是：在NET5下测试，无论是在小字节还是在多字节下，性能基本都差不多了，直接用系统的就可以了

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.17763.1282 (1809/October2018Update/Redstone5) Intel Core i7-8650U CPU 1.90GHz (Kaby Lake R), 1 CPU, 8 logical and 4 physical cores .NET Core SDK=5.0.100 [Host] : .NET Core 5.0.0 (CoreCLR 5.0.20.51904, CoreFX 5.0.20.51904), X64 RyuJIT Job-CNKWTZ : .NET Core 5.0.0 (CoreCLR 5.0.20.51904, CoreFX 5.0.20.51904), X64 RyuJIT RyuJitX64 : .NET Core 5.0.0 (CoreCLR 5.0.20.51904, CoreFX 5.0.20.51904), X64 RyuJIT

Jit=RyuJit Platform=X64

Method	Job	IterationCount	LaunchCount	RunStrategy	UnrollFactor	WarmupCount	Size	N	Mean	Error	StdDev	Ratio	RatioSD	Rank
UnsafeFastBufferCopyFixed	Job-CNKWTZ	2	1	ColdStart	1	1	96	10000000	64.83 ms	NA	23.979 ms	1.00	0.00	2
BlockCopy	Job-CNKWTZ	2	1	ColdStart	1	1	96	10000000	44.28 ms	NA	1.697 ms	0.74	0.30	1
UnsafeFastBufferCopyFixed	RyuJitX64	Default	Default	Default	16	Default	96	10000000	45.52 ms	0.597 ms	0.498 ms	1.00	0.00	2
BlockCopy	RyuJitX64	Default	Default	Default	16	Default	96	10000000	41.67 ms	0.744 ms	0.696 ms	0.91	0.02	1
UnsafeFastBufferCopyFixed	Job-CNKWTZ	2	1	ColdStart	1	1	508	10000000	192.71 ms	NA	1.022 ms	1.00	0.00	2
BlockCopy	Job-CNKWTZ	2	1	ColdStart	1	1	508	10000000	135.61 ms	NA	4.982 ms	0.70	0.02	1
UnsafeFastBufferCopyFixed	RyuJitX64	Default	Default	Default	16	Default	508	10000000	193.77 ms	3.392 ms	2.833 ms	1.00	0.00	2
BlockCopy	RyuJitX64	Default	Default	Default	16	Default	508	10000000	142.06 ms	1.158 ms	1.083 ms	0.73	0.01	1

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.17763.1282 (1809/October2018Update/Redstone5) Intel Core i7-8650U CPU 1.90GHz (Kaby Lake R), 1 CPU, 8 logical and 4 physical cores .NET Core SDK=5.0.100 [Host] : .NET Core 5.0.0 (CoreCLR 5.0.20.51904, CoreFX 5.0.20.51904), X64 RyuJIT RyuJitX64 : .NET Core 5.0.0 (CoreCLR 5.0.20.51904, CoreFX 5.0.20.51904), X64 RyuJIT

Job=RyuJitX64 Jit=RyuJit Platform=X64

Method	Size	N	Mean	Error	StdDev	Median	Ratio	RatioSD	Rank
UnsafeFastBufferCopyFixed	96	10000000	48.46 ms	1.368 ms	3.881 ms	47.03 ms	1.00	0.00	2
BlockCopy	96	10000000	41.79 ms	0.798 ms	0.819 ms	41.86 ms	0.85	0.06	1