func BytesRange(start []byte, end []byte) []byte
func Stride(ptr unsafe.Pointer, size uintptr, offset int) unsafe.Pointer
func SubsliceOffset(data []byte, subslice []byte) int
typeID is used as key in encoder and decoder caches to enable using the optimize runtime.mapaccess2_fast64 function instead of the more expensive lookup if we were to use reflect.Type as map key.
typeID holds the pointer to the reflect.Type value, which is unique in the program.
https://github.com/segmentio/encoding/blob/master/json/codec.go#L59-L61
type TypeID unsafe.Pointer
func MakeTypeID(t reflect.Type) TypeID