diff --git a/src/main/java/org/fluentd/logger/sender/AsyncRawSocketSender.java b/src/main/java/org/fluentd/logger/sender/AsyncRawSocketSender.java
index 8fc2d0b..daeba4b 100644
--- a/src/main/java/org/fluentd/logger/sender/AsyncRawSocketSender.java
+++ b/src/main/java/org/fluentd/logger/sender/AsyncRawSocketSender.java
@@ -24,7 +24,7 @@
  * @author mxk
  *
  */
-public class AsyncRawSocketSender implements Sender {
+public class AsyncRawSocketSender implements AsyncSender {
 
     private final class EmitRunnable implements Callable<Boolean> {
         private final String tag;
@@ -107,21 +107,14 @@ public void close() {
     }
 
     @Override
-    public boolean emit(String tag, Map<String, Object> data) {
+    public Future<Boolean> emit(String tag, Map<String, Object> data) {
         return emit(tag, System.currentTimeMillis() / 1000, data);
     }
 
     @Override
-    public boolean emit(final String tag, final long timestamp, final Map<String, Object> data) {
+    public Future<Boolean> emit(final String tag, final long timestamp, final Map<String, Object> data) {
         final RawSocketSender sender = this.sender;
-        try {
-            Future<Boolean> result = senderTask.submit(new EmitRunnable(tag, data, sender, timestamp));
-            return result.get();
-        } catch (InterruptedException e) {
-            throw new RuntimeException(e);
-        } catch (ExecutionException e) {
-            throw new RuntimeException(e);
-        }
+        return senderTask.submit(new EmitRunnable(tag, data, sender, timestamp));
     }
 
     @Override
diff --git a/src/main/java/org/fluentd/logger/sender/AsyncSender.java b/src/main/java/org/fluentd/logger/sender/AsyncSender.java
new file mode 100644
index 0000000..1e9d0a8
--- /dev/null
+++ b/src/main/java/org/fluentd/logger/sender/AsyncSender.java
@@ -0,0 +1,24 @@
+package org.fluentd.logger.sender;
+
+import org.fluentd.logger.errorhandler.ErrorHandler;
+
+import java.util.Map;
+import java.util.concurrent.Future;
+
+public interface AsyncSender {
+    Future<Boolean> emit(String tag, Map<String, Object> data);
+
+    Future<Boolean> emit(String tag, long timestamp, Map<String, Object> data);
+
+    void flush();
+
+    void close();
+
+    String getName();
+
+    boolean isConnected();
+
+    void setErrorHandler(ErrorHandler errorHandler);
+
+    void removeErrorHandler();
+}
diff --git a/src/test/java/org/fluentd/logger/sender/TestAsyncRawSocketSender.java b/src/test/java/org/fluentd/logger/sender/TestAsyncRawSocketSender.java
index 040a03f..7f581dd 100644
--- a/src/test/java/org/fluentd/logger/sender/TestAsyncRawSocketSender.java
+++ b/src/test/java/org/fluentd/logger/sender/TestAsyncRawSocketSender.java
@@ -17,8 +17,10 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -52,7 +54,7 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentd.waitUntilReady();
 
         // start asyncSenders
-        Sender asyncSender = new AsyncRawSocketSender("localhost", port);
+        AsyncSender asyncSender = new AsyncRawSocketSender("localhost", port);
         Map<String, Object> data = new HashMap<String, Object>();
         data.put("t1k1", "t1v1");
         data.put("t1k2", "t1v2");
@@ -115,7 +117,7 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentd.waitUntilReady();
 
         // start asyncSenders
-        Sender asyncSender = new AsyncRawSocketSender("localhost", port);
+        AsyncSender asyncSender = new AsyncRawSocketSender("localhost", port);
         int count = 10000;
         for (int i = 0; i < count; i++) {
             String tag = "tag:i";
@@ -186,7 +188,7 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentds[1].waitUntilReady();
 
         // start AsyncSenders
-        Sender[] asyncSenders = new Sender[2];
+        AsyncSender[] asyncSenders = new AsyncSender[2];
         int[] counts = new int[2];
         asyncSenders[0] = asyncRawSocketSender;
         counts[0] = 10000;
@@ -254,7 +256,7 @@ public void run() {
     }
 
     @Test
-    public void testBufferingAndResending() throws InterruptedException, IOException {
+    public void testBufferingAndResending() throws InterruptedException, IOException, ExecutionException {
         final ConcurrentLinkedQueue<Event> readEvents = new ConcurrentLinkedQueue<Event>();
         final CountDownLatch countDownLatch = new CountDownLatch(4);
         int port = MockFluentd.randomPort();
@@ -278,12 +280,12 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
         fluentd.start();
         fluentd.waitUntilReady();
 
-        Sender asyncSender = new AsyncRawSocketSender("localhost", port);
+        AsyncSender asyncSender = new AsyncRawSocketSender("localhost", port);
         assertFalse(asyncSender.isConnected());
         Map<String, Object> data = new HashMap<String, Object>();
         data.put("key0", "v0");
-        boolean emitted1 = asyncSender.emit("tag0", data);
-        assertTrue(emitted1);
+        Future<Boolean> emitted1 = asyncSender.emit("tag0", data);
+        assertTrue(emitted1.get());
 
         // close fluentd to make the next sending failed
         TimeUnit.MILLISECONDS.sleep(500);
@@ -294,21 +296,21 @@ public void process(MessagePack msgpack, Socket socket) throws IOException {
 
         data = new HashMap<String, Object>();
         data.put("key0", "v1");
-        boolean emitted2 = asyncSender.emit("tag0", data);
-        assertTrue(emitted2);
+        Future<Boolean> emitted2 = asyncSender.emit("tag0", data);
+        assertTrue(emitted2.get());
 
         // wait to avoid the suppression of reconnection
         TimeUnit.MILLISECONDS.sleep(500);
 
         data = new HashMap<String, Object>();
         data.put("key0", "v2");
-        boolean emitted3 = asyncSender.emit("tag0", data);
-        assertTrue(emitted3);
+        Future<Boolean> emitted3 = asyncSender.emit("tag0", data);
+        assertTrue(emitted3.get());
 
         data = new HashMap<String, Object>();
         data.put("key0", "v3");
-        boolean emitted4 = asyncSender.emit("tag0", data);
-        assertTrue(emitted4);
+        Future<Boolean> emitted4 = asyncSender.emit("tag0", data);
+        assertTrue(emitted4.get());
 
         countDownLatch.await(500, TimeUnit.MILLISECONDS);
 
@@ -382,7 +384,7 @@ public void run() {
         });
 
         // start asyncSenders
-        Sender asyncSender = new AsyncRawSocketSender("localhost", port);
+        AsyncSender asyncSender = new AsyncRawSocketSender("localhost", port);
         String tag = "tag";
         int i;
         for (i = 0; i < 1000000; i++) {     // Enough to fill the sender's buffer
@@ -392,7 +394,7 @@ public void run() {
 
             if (bufferFull.getCount() > 0) {
                 // Fill the sender's buffer
-                if (!asyncSender.emit(tag, record)) {
+                if (!asyncSender.emit(tag, record).get()) {
                     // Buffer full. Need to recover the fluentd
                     bufferFull.countDown();
                     Thread.sleep(2000);