| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go.opencensus.io/stats | Package stats contains support for OpenCensus stats recording. |
| go.opencensus.io/stats/view | Package view contains support for collecting and exposing aggregates over stats. |
| go.opencensus.io/trace | Package trace contains support for OpenCensus distributed tracing. |