Fix route_params::spawn to use capy::executor::post

Author: vinniefalco

src/server/route_handler.cpp

@@ -56,10 +56,30 @@ set_body(std::string s)
 auto
 route_params::
 spawn(
-    capy::task<route_result>) ->
+    capy::task<route_result> t) ->
         route_result
 {
-    detail::throw_invalid_argument();
+    return this->suspend(
+        [ex = this->ex, t = std::move(t)](resumer resume) mutable
+        {
+            auto h = t.release();
+
+            h.promise().on_done = [resume, h]()
+            {
+                auto& r = h.promise().result;
+                if(r.index() == 2)
+                {
+                    auto ep = std::get<2>(r);
+                    h.destroy();
+                    std::rethrow_exception(ep);
+                }
+                auto rv = std::move(std::get<1>(r));
+                h.destroy();
+                resume(rv);
+            };
+
+            ex.post([h]() { h.resume(); });
+        });
 }
 
 #endif