| encoding/gob | Package gob manages streams of gobs - binary values exchanged between an Encoder (transmitter) and a Decoder (receiver). |
| 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. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| 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. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |