| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/kylelemons/godebug/pretty | Package pretty pretty-prints Go structures. |
| io | Package io provides basic interfaces to I/O primitives. |
| net/http | Package http provides HTTP client and server implementations. |
| reflect | Package reflect implements run-time reflection, allowing a program to manipulate objects with arbitrary types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |