| crypto | Package crypto collects common cryptographic constants. |
| encoding/binary | Package binary implements simple translation between numbers and byte sequences and encoding and decoding of varints. |
| errors | Package errors implements functions to manipulate errors. |
| hash | Package hash provides interfaces for hash functions. |
| internal/cpu | Package cpu implements processor feature detection used by the Go standard library. |
| math/bits | Package bits implements bit counting and manipulation functions for the predeclared unsigned integer types. |