delete files

src/main/java/com/microsoft/azure/kusto/kafka/connect/sink/FileWriter.java

@@ -114,6 +114,7 @@ public class FileWriter implements Closeable {
             }
 
             onRollCallback.accept(currentFile);
+            currentFile.file.delete();
         }
 
         // closing late so that the success callback will have a chance to use the file. This is a real thing on debug?!

src/main/java/com/microsoft/azure/kusto/kafka/connect/sink/TopicPartitionWriter.java

@@ -1,8 +1,6 @@
 package com.microsoft.azure.kusto.kafka.connect.sink;
 
-import com.microsoft.azure.kusto.data.ConnectionStringBuilder;
 import com.microsoft.azure.kusto.ingest.IngestClient;
-import com.microsoft.azure.kusto.ingest.IngestClientFactory;
 import com.microsoft.azure.kusto.ingest.IngestionProperties;
 import com.microsoft.azure.kusto.ingest.source.CompressionType;
 import com.microsoft.azure.kusto.ingest.source.FileSourceInfo;