AddHeader creates the given set of headers if needed, and then adds the given header:.

AddValue creates the given set of query parameters if needed, an then adds the given parameter.

CopyQuery creates a copy of the given set of query parameters.

CopyValues copies a slice of strings.

NewDecoder creates a new JSON decoder from the given source.

NewEncoder creates a new JSON encoder from the given target.

SetHeader creates a copy of the given set of headers, and adds the header containing the given metrics path.