Fixed timer usage inside basic_stream.

Closes #2602.

include/boost/beast/websocket/impl/stream_impl.hpp

@@ -68,8 +68,9 @@ struct stream<NextLayer, deflateSupported>::impl_type
             impl_type>(this->detail::service::
                 impl_type::shared_from_this());
     }
-
-    net::steady_timer       timer;          // used for timeouts
+    using executor_type = typename std::decay<NextLayer>::type::executor_type;
+    typename net::steady_timer::rebind_executor<executor_type>::other
+                            timer;          // used for timeouts
     close_reason            cr;             // set from received close frame
     control_cb_type         ctrl_cb;        // control callback
 

test/beast/core/tcp_stream.cpp

@@ -15,6 +15,12 @@
 namespace boost {
 namespace beast {
 
+// compile test for other exec
+template class basic_stream<
+        net::ip::tcp,
+        net::io_context::executor_type,
+        unlimited_rate_policy> ;
+
 class tcp_stream_test
     : public beast::unit_test::suite
 {