-type buoy_resp() ::
          #buoy_resp{state :: body | done,
                     body :: undefined | binary(),
                     content_length :: undefined | non_neg_integer() | chunked,
                     headers :: undefined | [binary()],
                     reason :: undefined | binary(),
                     status_code :: undefined | 100..505}.

-type buoy_url() ::
          #buoy_url{host :: host(),
                    hostname :: hostname(),
                    path :: path(),
                    port :: inet:port_number(),
                    protocol :: protocol_http()}.

-type error() :: {error, term()}.

-type error_reason() ::
          pool_not_started | buoy_not_started | pool_already_started | invalid_url | invalid_headers |
          invalid_chunk_size | no_server | shackle_not_started | timeout.

-type host() :: binary().

-type hostname() :: binary().

-type path() :: binary().

-type protocol_http() :: http | https.