DAP: allow custom request extension in Session class

Author: ono-max

lib/debug/server_dap.rb

@@ -651,7 +651,11 @@ def process_protocol_request req
           fail_response req
         end
       else
-        raise "Unknown DAP request: #{req.inspect}"
+        if respond_to? mid = "request_#{req['command']}"
+          send mid, req
+        else
+          raise "Unknown request: #{req.inspect}"
+        end
       end
     end