diff --git a/lib/membrane_rtmp_plugin/rtmp_server.ex b/lib/membrane_rtmp_plugin/rtmp_server.ex
index 19ce194..0639347 100644
--- a/lib/membrane_rtmp_plugin/rtmp_server.ex
+++ b/lib/membrane_rtmp_plugin/rtmp_server.ex
@@ -27,9 +27,8 @@ defmodule Membrane.RTMPServer do
           port: :inet.port_number(),
           use_ssl?: boolean(),
           name: atom() | nil,
-          handle_new_client:
-            (client_ref :: pid(), app :: String.t(), stream_key :: String.t() ->
-               client_behaviour_spec()),
+          handle_new_client: (client_ref :: pid(), app :: String.t(), stream_key :: String.t() ->
+                                client_behaviour_spec()),
           client_timeout: Membrane.Time.t()
         ]
 
@@ -46,7 +45,13 @@ defmodule Membrane.RTMPServer do
   an input argument of the `c:#{inspect(ClientHandler)}.handle_init/1`. Otherwise, an empty
   map is passed to the `c:#{inspect(ClientHandler)}.handle_init/1`.
   """
-  @type client_behaviour_spec :: ClientHandler.t() | {ClientHandler.t(), opts :: any()}
+
+  @type receiver_pid :: pid() | nil
+
+  @type client_behaviour_spec ::
+          ClientHandler.t()
+          | {ClientHandler.t(), opts :: any()}
+          | {CLientHandler.t(), opts :: any(), receiver_pid}
 
   @type server_identifier :: pid() | atom()