Forward declare asio::ssl::stream to avoid OpenSSL dependancy

Summary: related to T13767, #14

Reviewers: ivica

Reviewed By: ivica

Subscribers: iljazovic, miljen

Differential Revision: https://repo.mireo.local/D31524

include/async_mqtt5/detail/rebind_executor.hpp

@@ -8,10 +8,16 @@
 #ifndef ASYNC_MQTT5_REBIND_EXECUTOR_HPP
 #define ASYNC_MQTT5_REBIND_EXECUTOR_HPP
 
-#include <boost/asio/ssl/stream.hpp>
-
 #include <boost/beast/websocket/stream.hpp>
 
+namespace boost::asio::ssl {
+
+// forward declare to preserve optional OpenSSL dependency
+template <typename Stream>
+class stream;
+
+} // end namespace boost::asio::ssl
+
 namespace async_mqtt5::detail {
 
 namespace asio = boost::asio;