| compress/zlib | Package zlib implements reading and writing of zlib format compressed data, as specified in RFC 1950. |
| 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. |
| io | Package io provides basic interfaces to I/O primitives. |
| math | Package math provides basic constants and mathematical functions. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |