message: udp proxy: fix test flake
diff: @@ -92,8 +92,10 @@ public:
  EXPECT_EQ(5, test_server_->counter("udp.foo.downstream_sess_rx_bytes")->value());
  EXPECT_EQ(1, test_server_->counter("udp.foo.downstream_sess_rx_datagrams")->value());
  - EXPECT_EQ(6, test_server_->counter("udp.foo.downstream_sess_tx_bytes")->value());
  - EXPECT_EQ(1, test_server_->counter("udp.foo.downstream_sess_tx_datagrams")->value());
  + // The stat is incremented after the send so there is a race condition and we must wait for
  + // the counter to be incremented.
  + test_server_->waitForCounterEq("udp.foo.downstream_sess_tx_bytes", 6);
  + test_server_->waitForCounterEq("udp.foo.downstream_sess_tx_datagrams", 1);
  EXPECT_EQ(1, test_server_->counter("udp.foo.downstream_sess_total")->value());
  EXPECT_EQ(1, test_server_->gauge("udp.foo.downstream_sess_active")->value());
  }
  