| bytes | Package bytes implements functions for the manipulation of byte slices. |
| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| errors | Package errors implements functions to manipulate errors. |
| io | Package io provides basic interfaces to I/O primitives. |
| log | Package log implements a simple logging package. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |