diff --git a/lib/erl/src/thrift_http_transport.erl b/lib/erl/src/thrift_http_transport.erl
index 09113cc..7d0226f 100644
--- a/lib/erl/src/thrift_http_transport.erl
+++ b/lib/erl/src/thrift_http_transport.erl
@@ -34,7 +34,7 @@
                          http_options, % see http(3)
                          extra_headers % [{str(), str()}, ...]
                         }).
--type state() :: pid().
+-type state() :: #http_transport{}.
 -include("thrift_transport_behaviour.hrl").
 
 new(Host, Path) ->