name() :: %Sippet.Transactions.Server{branch: term, method: term, sent_by: term}
request() :: %Sippet.Message{body: term, headers: term, start_line: %Sippet.Message.RequestLine{method: term, request_uri: term, version: term}, target: term}
t() :: [request: request, name: name, extras: %{}]