CXP-3032: Race condition during local.buffer.dir creation

When multiple tasks are starte on the same worker all of them are
trying to check if the directory exists and create if not. Sometimes
some of the tasks fail because the directory gets created after
the existence check and before the creation attempt by other tasks.

The fix is to do a few attempts of checking and creating the directory.

build.gradle

@@ -13,7 +13,7 @@ allprojects {
 	apply plugin: 'maven-publish'
 
 	group = 'com.spredfast.kafka.connect.s3'
-	version = '1.2.0'
+	version = '1.2.1'
 
 	apply plugin: 'java-library'
 	sourceCompatibility = 11

sink/src/main/java/com/spredfast/kafka/connect/s3/sink/S3SinkTask.java

@@ -233,7 +233,11 @@ private PartitionWriter(TopicPartition tp, SinkRecord firstRecord) throws IOExce
               .orElseThrow(() -> new ConnectException("No local buffer directory configured"));
 
       File directory = new File(localBufferDirectory);
-      if (!directory.exists() && !directory.mkdirs()) {
+      int attempts = 3;
+      while (attempts > 0 && !directory.exists() && !directory.mkdirs()) {
+        attempts--;
+      }
+      if (!directory.exists()) {
         throw new ConnectException("Could not create directory " + localBufferDirectory);
       }