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

-type error_reason() ::
          auth_continue | auth_error | busy | incr_non_numeric | internal_error | invalid_args |
          item_not_stored | key_exists | key_not_found | not_supported | out_of_memory | temp_failure |
          unknown_command | value_too_large | vbucket_error | no_server | pool_not_started |
          shackle_not_started | timeout.

-type option() :: {async, pid()}.

-type options() :: [option()].

-type response() ::
          #response{op_code :: non_neg_integer() | undefined,
                    key_length :: non_neg_integer() | undefined,
                    extras_length :: non_neg_integer() | undefined,
                    data_type :: non_neg_integer() | undefined,
                    status :: non_neg_integer() | undefined,
                    body_length :: non_neg_integer() | undefined,
                    opaque :: non_neg_integer() | undefined,
                    cas :: non_neg_integer() | undefined,
                    extras :: binary() | undefined,
                    key :: binary() | undefined,
                    value :: binary() | undefined}.