| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/golang/protobuf/proto | Package proto provides functionality for handling protocol buffer messages. |
| github.com/openzipkin/zipkin-go/model | Package model contains the Zipkin V2 model which is used by the Zipkin Go tracer implementation. |
| math | Package math provides basic constants and mathematical functions. |
| net | Package net provides a portable interface for network I/O, including TCP/IP, UDP, domain name resolution, and Unix domain sockets. |
| time | Package time provides functionality for measuring and displaying time. |