Use RequestNotExecutedException instead of ConnectionClosedException when failing enqueued requests that never got executed

Author: ok2c

httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java

@@ -580,7 +580,7 @@ public final void onDisconnect() {
             final Command command = ioSession.poll();
             if (command != null) {
                 if (command instanceof ExecutableCommand) {
-                    ((ExecutableCommand) command).failed(new ConnectionClosedException());
+                    ((ExecutableCommand) command).failed(new RequestNotExecutedException());
                 } else {
                     command.cancel();
                 }
@@ -666,7 +666,7 @@ public final void onException(final Exception cause) {
                 final Command command = ioSession.poll();
                 if (command != null) {
                     if (command instanceof ExecutableCommand) {
-                        ((ExecutableCommand) command).failed(new ConnectionClosedException());
+                        ((ExecutableCommand) command).failed(new RequestNotExecutedException());
                     } else {
                         command.cancel();
                     }