| errors | Package errors implements functions to manipulate errors. |
| go.opencensus.io/metric | Package metric support for gauge and cumulative metrics. |
| go.opencensus.io/metric/metricdata | Package metricdata contains the metrics data model. |
| go.opencensus.io/metric/metricproducer | |
| runtime | Package runtime contains operations that interact with Go's runtime system, such as functions to control goroutines. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |
| time | Package time provides functionality for measuring and displaying time. |