diff --git a/pom.xml b/pom.xml
index 91973e0..1a0e254 100644
--- a/pom.xml
+++ b/pom.xml
@@ -135,6 +135,11 @@
             <artifactId>common-utils</artifactId>
             <version>1.1.2</version>
         </dependency>
+        <dependency>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-tcnative-boringssl-static</artifactId>
+            <version>2.0.30.Final</version>
+        </dependency>
 
         <dependency>
             <groupId>it.tdlight</groupId>
diff --git a/src/main/java/it/tdlight/tdlibsession/remoteclient/TDLibRemoteClient.java b/src/main/java/it/tdlight/tdlibsession/remoteclient/TDLibRemoteClient.java
index b6879dd..aa32f81 100644
--- a/src/main/java/it/tdlight/tdlibsession/remoteclient/TDLibRemoteClient.java
+++ b/src/main/java/it/tdlight/tdlibsession/remoteclient/TDLibRemoteClient.java
@@ -170,6 +170,10 @@ public class TDLibRemoteClient implements AutoCloseable {
 									.chooseBinlog(clusterManager.getVertx().fileSystem(), blPath, req.binlog(), req.binlogDate())
 									.then(BinlogUtils.cleanSessionPath(clusterManager.getVertx().fileSystem(), blPath, sessPath, mediaPath))
 									.then(clusterManager.getVertx().rxDeployVerticle(verticle, deploymentOptions).as(MonoUtils::toMono))
+									.then(MonoUtils.fromBlockingMaybe(() -> {
+										msg.reply(new byte[0]);
+										return null;
+									}))
 									.publishOn(Schedulers.single())
 									.subscribe(
 											v -> {},
@@ -177,7 +181,7 @@ public class TDLibRemoteClient implements AutoCloseable {
 												logger.error("Failed to deploy bot verticle", ex);
 												msg.fail(500, "Failed to deploy bot verticle: " + ex.getMessage());
 											},
-											() -> msg.reply(new byte[0])
+											() -> {}
 									);
 						});
 					});
diff --git a/src/main/java/it/tdlight/tdlibsession/td/direct/AsyncTdDirectImpl.java b/src/main/java/it/tdlight/tdlibsession/td/direct/AsyncTdDirectImpl.java
index c3580de..c24e856 100644
--- a/src/main/java/it/tdlight/tdlibsession/td/direct/AsyncTdDirectImpl.java
+++ b/src/main/java/it/tdlight/tdlibsession/td/direct/AsyncTdDirectImpl.java
@@ -106,7 +106,8 @@ public class AsyncTdDirectImpl implements AsyncTdDirect {
 							});
 						})
 						.subscribeOn(Schedulers.boundedElastic())
-						.publishOn(Schedulers.single())
-				);
+						.publishOn(Schedulers.boundedElastic())
+				)
+				.subscribeOn(Schedulers.boundedElastic());
 	}
 }
diff --git a/src/main/java/it/tdlight/tdlibsession/td/middle/TdClusterManager.java b/src/main/java/it/tdlight/tdlibsession/td/middle/TdClusterManager.java
index 32f7909..af2be5a 100644
--- a/src/main/java/it/tdlight/tdlibsession/td/middle/TdClusterManager.java
+++ b/src/main/java/it/tdlight/tdlibsession/td/middle/TdClusterManager.java
@@ -154,21 +154,25 @@ public class TdClusterManager {
 			vertxOptions.getEventBusOptions().setTrustStoreOptions(trustStoreOptions);
 			vertxOptions.getEventBusOptions().setHost(masterHostname);
 			vertxOptions.getEventBusOptions().setPort(port + 1);
-			vertxOptions.getEventBusOptions().setSsl(true).setEnabledSecureTransportProtocols(Set.of("TLSv1.3", "TLSv1.2"));
+			vertxOptions
+					.getEventBusOptions()
+					.setUseAlpn(true)
+					.setSsl(true)
+					.setEnabledSecureTransportProtocols(Set.of("TLSv1.3", "TLSv1.2"));
 			vertxOptions.getEventBusOptions().setClientAuth(ClientAuth.REQUIRED);
 		} else {
 			mgr = null;
 			vertxOptions.setClusterManager(null);
 		}
 
-		vertxOptions.setPreferNativeTransport(false);
+		vertxOptions.setPreferNativeTransport(true);
 		vertxOptions.setMetricsOptions(new MetricsOptions().setEnabled(false));
 		// check for blocked threads every 5s
 		vertxOptions.setBlockedThreadCheckInterval(5);
 		vertxOptions.setBlockedThreadCheckIntervalUnit(TimeUnit.SECONDS);
-		// warn if an event loop thread handler took more than 100ms to execute
-		vertxOptions.setMaxEventLoopExecuteTime(100);
-		vertxOptions.setMaxEventLoopExecuteTimeUnit(TimeUnit.MILLISECONDS);
+		// warn if an event loop thread handler took more than 10s to execute
+		vertxOptions.setMaxEventLoopExecuteTime(10);
+		vertxOptions.setMaxEventLoopExecuteTimeUnit(TimeUnit.SECONDS);
 		// warn if an worker thread handler took more than 10s to execute
 		vertxOptions.setMaxWorkerExecuteTime(10);
 		vertxOptions.setMaxWorkerExecuteTimeUnit(TimeUnit.SECONDS);
@@ -177,14 +181,14 @@ public class TdClusterManager {
 		vertxOptions.setWarningExceptionTimeUnit(TimeUnit.MILLISECONDS);
 
 		return Mono
-				.<Vertx>create(sink -> {
+				.defer(() -> {
 					if (mgr != null) {
-						Vertx.clusteredVertx(vertxOptions, MonoUtils.toHandler(sink));
+						return Vertx.rxClusteredVertx(vertxOptions).as(MonoUtils::toMono).subscribeOn(Schedulers.boundedElastic());
 					} else {
-						sink.success(Vertx.vertx(vertxOptions));
+						return Mono.just(Vertx.vertx(vertxOptions));
 					}
 				})
-				.publishOn(Schedulers.boundedElastic())
+				.publishOn(Schedulers.single())
 				.flatMap(vertx -> Mono
 						.fromCallable(() -> new TdClusterManager(mgr, vertxOptions, vertx))
 						.publishOn(Schedulers.boundedElastic())
diff --git a/src/main/java/it/tdlight/tdlibsession/td/middle/client/AsyncTdMiddleEventBusClient.java b/src/main/java/it/tdlight/tdlibsession/td/middle/client/AsyncTdMiddleEventBusClient.java
index c72649b..b197813 100644
--- a/src/main/java/it/tdlight/tdlibsession/td/middle/client/AsyncTdMiddleEventBusClient.java
+++ b/src/main/java/it/tdlight/tdlibsession/td/middle/client/AsyncTdMiddleEventBusClient.java
@@ -170,16 +170,15 @@ public class AsyncTdMiddleEventBusClient implements AsyncTdMiddle {
 				.timeout(Duration.ofSeconds(5))
 				.publishOn(Schedulers.single())
 				.flatMapMany(tdResultListFlux -> tdResultListFlux.publishOn(Schedulers.single()))
-				.startWith(MonoUtils
-						.castVoid(Mono.<Void>fromRunnable(() -> {
-							cluster.getEventBus().<byte[]>send(botAddress + ".ready-to-receive", EMPTY, deliveryOptionsWithTimeout);
-						}).subscribeOn(Schedulers.boundedElastic()))
-				)
 				.timeout(Duration.ofMinutes(1), Mono.fromCallable(() -> {
 					var ex = new ConnectException("Server did not respond to 12 pings after 1 minute (5 seconds per ping)");
 					ex.setStackTrace(new StackTraceElement[0]);
 					throw ex;
 				}))
+				.doOnSubscribe(s -> cluster.getEventBus().<byte[]>send(botAddress + ".ready-to-receive",
+						EMPTY,
+						deliveryOptionsWithTimeout
+				))
 				.flatMapSequential(updates -> {
 					if (updates.succeeded()) {
 						return Flux.fromIterable(updates.value());
diff --git a/src/main/java/it/tdlight/tdlibsession/td/middle/direct/AsyncTdMiddleDirect.java b/src/main/java/it/tdlight/tdlibsession/td/middle/direct/AsyncTdMiddleDirect.java
index e4cc7da..7a0dc9e 100644
--- a/src/main/java/it/tdlight/tdlibsession/td/middle/direct/AsyncTdMiddleDirect.java
+++ b/src/main/java/it/tdlight/tdlibsession/td/middle/direct/AsyncTdMiddleDirect.java
@@ -91,6 +91,7 @@ public class AsyncTdMiddleDirect extends AbstractVerticle implements AsyncTdMidd
 				.doOnNext(s -> logger.trace("Received update from tdlib: {}", s))
 				.doOnError(ex -> logger.info("TdMiddle verticle error", ex))
 				.doOnTerminate(() -> logger.debug("TdMiddle verticle stopped"))
+				.subscribeOn(Schedulers.boundedElastic())
 				.publishOn(Schedulers.single());
 	}
 
diff --git a/src/main/java/it/tdlight/tdlibsession/td/middle/server/AsyncTdMiddleEventBusServer.java b/src/main/java/it/tdlight/tdlibsession/td/middle/server/AsyncTdMiddleEventBusServer.java
index cda42d2..d048376 100644
--- a/src/main/java/it/tdlight/tdlibsession/td/middle/server/AsyncTdMiddleEventBusServer.java
+++ b/src/main/java/it/tdlight/tdlibsession/td/middle/server/AsyncTdMiddleEventBusServer.java
@@ -327,7 +327,7 @@ public class AsyncTdMiddleEventBusServer extends AbstractVerticle {
 					}
 					return false;
 				})
-				.flatMapSequential(update -> Mono.fromCallable(() -> {
+				.flatMapSequential(update -> MonoUtils.fromBlockingSingle(() -> {
 					if (update.getConstructor() == TdApi.Error.CONSTRUCTOR) {
 						var error = (Error) update;
 						throw new TdError(error.code, error.message);
diff --git a/src/main/java/it/tdlight/utils/BatchSubscriber.java b/src/main/java/it/tdlight/utils/BatchSubscriber.java
new file mode 100644
index 0000000..82a6876
--- /dev/null
+++ b/src/main/java/it/tdlight/utils/BatchSubscriber.java
@@ -0,0 +1,154 @@
+package it.tdlight.utils;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.atomic.AtomicReferenceFieldUpdater.newUpdater;
+import static reactor.core.Exceptions.addSuppressed;
+import static reactor.core.publisher.Operators.cancelledSubscription;
+import static reactor.core.publisher.Operators.onErrorDropped;
+import static reactor.core.publisher.Operators.onOperatorError;
+import static reactor.core.publisher.Operators.setOnce;
+import static reactor.core.publisher.Operators.terminate;
+import static reactor.core.scheduler.Schedulers.parallel;
+
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
+import org.reactivestreams.Subscription;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import reactor.core.CoreSubscriber;
+import reactor.core.Disposable;
+import reactor.core.scheduler.Scheduler;
+
+public abstract class BatchSubscriber<T> implements CoreSubscriber<T> {
+
+	private static final Logger log = LoggerFactory.getLogger(BatchSubscriber.class);
+
+	private final Scheduler scheduler;
+	private final int batchSize;
+	private final Duration timeout;
+
+	private final BlockingQueue<T> buffer = new LinkedBlockingQueue<>();
+	private final AtomicInteger requests = new AtomicInteger(0);
+
+	private final AtomicReference<Disposable> flushTimer = new AtomicReference<>();
+	private final Runnable flushTask = () -> {
+		log.trace("timeout [{}] -> flush", buffer.size());
+		flush();
+	};
+
+	private volatile Subscription subscription;
+	private static AtomicReferenceFieldUpdater<BatchSubscriber, Subscription> S = newUpdater(BatchSubscriber.class, Subscription.class, "subscription");
+
+	public BatchSubscriber(int batchSize, Duration timeout) {
+		this.batchSize = batchSize;
+		this.timeout = timeout;
+		this.scheduler = parallel();
+	}
+
+	@Override
+	public void onSubscribe(Subscription s) {
+		setOnce(S, this, s);
+	}
+
+	@Override
+	public void onNext(T record) {
+		try {
+			buffer.add(record);
+			if (requests.get() > 0) {
+				if (buffer.size() >= batchSize) {
+					log.trace("+ value [{}] -> flush", buffer.size());
+					flush();
+				}
+				else {
+					log.trace("+ value [{}] -> flush in {}ms", buffer.size(), timeout.toMillis());
+					scheduleFlush();
+				}
+			}
+			else {
+				log.trace("+ value [{}] -> buffer", buffer.size());
+			}
+		}
+		catch (Throwable t) {
+			onError(onOperatorError(subscription, t, record, currentContext()));
+		}
+	}
+
+	@Override
+	public void onError(Throwable t) {
+		if (S.getAndSet(this, cancelledSubscription()) != cancelledSubscription()) {
+			try {
+				suspendFlush();
+			}
+			catch (Throwable e) {
+				t = addSuppressed(e, t);
+			}
+		}
+
+		onErrorDropped(t, currentContext());
+	}
+
+	@Override
+	public void onComplete() {
+		if (S.getAndSet(this, cancelledSubscription()) != cancelledSubscription()) {
+			try {
+				suspendFlush();
+			}
+			catch (Throwable e) { }
+		}
+	}
+
+	// Implement what to do with a batch (either full or partial due to timeout).
+	// Could be publish to another subscriber.
+	public abstract void flush(List<T> batch);
+
+	private void flush() {
+		suspendFlush();
+
+		List<T> batch = new ArrayList<>(batchSize);
+		buffer.drainTo(batch, batchSize);
+		flush(batch);
+
+		requests.decrementAndGet();
+		log.trace("- request [{}]", requests.get());
+	}
+
+	private void scheduleFlush() {
+		flushTimer.updateAndGet(current -> {
+			if (current != null) current.dispose();
+			return scheduler.schedule(flushTask, timeout.toMillis(), MILLISECONDS);
+		});
+	}
+
+	private void suspendFlush() {
+		flushTimer.updateAndGet(current -> {
+			if (current != null) current.dispose();
+			return null;
+		});
+	}
+
+	public void request() {
+		if (requests.get() == 0 && buffer.size() >= batchSize) {
+			log.trace(". request [{}] -> flush", buffer.size());
+			flush();
+		}
+		else {
+			int required = requests.incrementAndGet() == 1
+					? batchSize - buffer.size()
+					: batchSize;
+			log.trace("+ request [{}] -> request {} values", buffer.size(), required);
+			subscription.request(required);
+
+			if (!buffer.isEmpty()) scheduleFlush();
+		}
+	}
+
+	public void cancel() {
+		terminate(S, this);
+	}
+}
\ No newline at end of file
diff --git a/src/main/java/it/tdlight/utils/MonoUtils.java b/src/main/java/it/tdlight/utils/MonoUtils.java
index 27b5d98..8492f6b 100644
--- a/src/main/java/it/tdlight/utils/MonoUtils.java
+++ b/src/main/java/it/tdlight/utils/MonoUtils.java
@@ -100,7 +100,7 @@ public class MonoUtils {
 	}
 
 	public static <T> Mono<T> fromBlockingMaybe(Callable<T> callable) {
-		return Mono.fromCallable(callable).subscribeOn(Schedulers.boundedElastic()).publishOn(Schedulers.single());
+		return Mono.fromCallable(callable).subscribeOn(Schedulers.boundedElastic());
 	}
 
 	public static <T> Mono<T> fromBlockingSingle(Callable<T> callable) {
@@ -230,15 +230,15 @@ public class MonoUtils {
 	}
 
 	public static <T> Mono<T> toMono(Single<T> single) {
-		return Mono.fromDirect(single.toFlowable());
+		return Mono.from(single.toFlowable());
 	}
 
 	public static <T> Mono<T> toMono(Maybe<T> single) {
-		return Mono.fromDirect(single.toFlowable());
+		return Mono.from(single.toFlowable());
 	}
 
 	public static <T> Mono<T> toMono(Completable completable) {
-		return Mono.fromDirect(completable.toFlowable());
+		return Mono.from(completable.toFlowable());
 	}
 
 	public static <T> Completable toCompletable(Mono<T> s) {
@@ -348,8 +348,7 @@ public class MonoUtils {
 			sink.onDispose(messageConsumer::unregister);
 		})
 				.subscribeOn(Schedulers.boundedElastic())
-				.publishOn(Schedulers.single())
-				.flatMapSequential(msg -> Mono.fromCallable(msg::body).publishOn(Schedulers.boundedElastic()));
+				.flatMapSequential(msg -> Mono.fromCallable(msg::body).subscribeOn(Schedulers.boundedElastic()));
 	}
 
 	public static class SinkRWStream<T> implements io.vertx.core.streams.WriteStream<T>, io.vertx.core.streams.ReadStream<T> {