| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| errors | Package errors implements functions to manipulate errors. |
| github.com/google/martian/v3 | Package martian provides an HTTP/1.1 proxy with an API for configurable request and response modifiers. |
| github.com/google/martian/v3/parse | Package parse constructs martian modifiers from JSON messages. |
| net/http | Package http provides HTTP client and server implementations. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |