| bytes | Package bytes implements functions for the manipulation of byte slices. |
| crypto/sha256 | Package sha256 implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-4. |
| 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. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/constant | Package constant implements Values representing untyped Go constants and their corresponding operations. |
| go/token | Package token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates). |
| io | Package io provides basic interfaces to I/O primitives. |
| math/big | Package big implements arbitrary-precision arithmetic (big numbers). |
| os | Package os provides a platform-independent interface to operating system functionality. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |