DBZ-1889 Prevent Connect throttling while connection is down

debezium-core/src/main/java/io/debezium/connector/common/BaseSourceTask.java

@@ -34,6 +34,8 @@
  */
 public abstract class BaseSourceTask extends SourceTask {
 
+    private static final int PAUSE_WHEN_NOT_STARTED = 2_000;
+
     private static final Logger LOGGER = LoggerFactory.getLogger(BaseSourceTask.class);
 
     protected static enum State {
@@ -117,6 +119,10 @@ public final List<SourceRecord> poll() throws InterruptedException {
 
         // in backoff period after a retriable exception
         if (!started) {
+            // WorkerSourceTask calls us immediately after we return the empty list.
+            // This turns into a throttling so we need to make a pause before we return
+            // the control back.
+            Thread.sleep(PAUSE_WHEN_NOT_STARTED);
             return Collections.emptyList();
         }