| bufio | Package bufio implements buffered I/O. |
| bytes | Package bytes implements functions for the manipulation of byte slices. |
| crypto/rand | Package rand implements a cryptographically secure pseudorandom number generator. |
| crypto/sha1 | Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174. |
| crypto/tls | Package tls partially implements TLS 1.2, as specified in RFC 5246. |
| encoding/base64 | Package base64 implements base64 encoding as specified by RFC 4648. |
| encoding/binary | Package binary implements simple translation between numbers and byte sequences and encoding and decoding of varints. |
| encoding/json | Package json implements encoding and decoding of JSON objects as defined in RFC 4627. |
| 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. |
| io/ioutil | Package ioutil implements some I/O utility functions. |
| 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. |
| net/url | Package url parses URLs and implements query escaping. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |