fix: Handle exception closing stream for unavailable adapter on windows. (#427)

On windows shutting down a stream for an adapter that is no longer
available would crash. I was testing this by disabling adapters, but my
suspicion is after a computer sleeps it may take some time for the
adapters to recover on windows.

Author: kinyoklion

libs/server-sent-events/src/client.cpp

@@ -341,13 +341,21 @@ class FoxyClient : public Client,
         // If any backoff is taking place, cancel that as well.
         backoff_timer_.cancel();
 
-        // Cancels the outstanding read.
-        if (session_->stream.is_ssl()) {
-            session_->stream.ssl().next_layer().cancel();
-        } else {
-            session_->stream.plain().cancel();
+        try {
+            // Cancels the outstanding read.
+            if (session_->stream.is_ssl()) {
+                session_->stream.ssl().next_layer().cancel();
+            } else {
+                session_->stream.plain().cancel();
+            }
+        } catch (boost::system::system_error const& err) {
+            // The stream is likely already closed. Potentially the network
+            // interface that was associated with the stream is no longer
+            // available.
+            logger_("exception closing stream: " + std::string(err.what()));
         }
 
+
         // Ideally we would call session_->async_shutdown() here to gracefully
         // terminate the SSL session. For unknown reasons, this call appears to
         // hang indefinitely and never complete until the SDK client is