added more metrics to statement_cache

source/orm/sql/statement_cache.cpp

@@ -40,16 +40,23 @@ public:
           "Failed to execute statement because it is already in use"
         });
       }
+      metrics.lock_acquired = std::chrono::steady_clock::now();
+      // publish
 
       auto guard = statement_guard(*this);
-      if (auto conn = pool_.acquire(connection_id_); !conn.valid()) {
+      if (const auto conn = pool_.acquire(connection_id_); !conn.valid()) {
         return utils::failure(utils::error{
           error_code::EXECUTE_FAILED,
           "Failed to execute statement because couldn't lock connection"
         });
       }
 
-      return statement_->execute(bindings);
+      metrics.execution_start = std::chrono::steady_clock::now();
+      auto execution_result = statement_->execute(bindings);
+      metrics.execution_end = std::chrono::steady_clock::now();
+
+      // publish
+      return execution_result;
     });
 
     return result;