| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| crypto/tls | Package tls partially implements TLS 1.2, as specified in RFC 5246, and TLS 1.3, as specified in RFC 8446. |
| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| net/http | Package http provides HTTP client and server implementations. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| syscall | Package syscall contains an interface to the low-level operating system primitives. |
| time | Package time provides functionality for measuring and displaying time. |