| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| errors | Package errors implements functions to manipulate errors. |
| golang.org/x/sync/errgroup | Package errgroup provides synchronization, error propagation, and Context cancelation for groups of goroutines working on subtasks of a common task. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |