System.Runtime by Microsoft

<PackageReference Include="System.Runtime" Version="4.0.20-beta-22605" />

.NET API 126,264 bytes

 Buffer

public static class Buffer
public static void BlockCopy(Array src, int srcOffset, Array dst, int dstOffset, int count)

public static int ByteLength(Array array)

public static byte GetByte(Array array, int index)

public static void MemoryCopy(Void* source, Void* destination, long destinationSizeInBytes, long sourceBytesToCopy)

public static void MemoryCopy(Void* source, Void* destination, ulong destinationSizeInBytes, ulong sourceBytesToCopy)

public static void SetByte(Array array, int index, byte value)