enable TcpClient metrics

Author: rxdcxdrnine

r2dbc-mysql/src/main/java/io/asyncer/r2dbc/mysql/client/Client.java

@@ -29,6 +29,7 @@
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.core.publisher.SynchronousSink;
+import reactor.netty.internal.util.Metrics;
 import reactor.netty.resources.LoopResources;
 import reactor.netty.tcp.TcpClient;
 
@@ -155,6 +156,10 @@ static Mono<Client> connect(MySqlSslConfiguration ssl, SocketAddress address, bo
             tcpClient = tcpClient.resolver(resolver);
         }
 
+        if (Metrics.isMicrometerAvailable()) {
+            tcpClient.metrics(true);
+        }
+
         return tcpClient.remoteAddress(() -> address).connect()
             .map(conn -> new ReactorNettyClient(conn, ssl, context));
     }