| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| internal/poll | Package poll supports non-blocking I/O on file descriptors with polling. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| slices | Package slices defines various functions useful with slices of any type. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| time | Package time provides functionality for measuring and displaying time. |
| unsafe | Package unsafe contains operations that step around the type safety of Go programs. |