Remove unused import

Author: davidh44

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/async/ByteArraySplittingTransformer.java

@@ -34,7 +34,6 @@
 import software.amazon.awssdk.core.exception.SdkClientException;
 import software.amazon.awssdk.utils.CompletableFutureUtils;
 import software.amazon.awssdk.utils.Logger;
-import software.amazon.awssdk.utils.async.DelegatingBufferingSubscriber;
 import software.amazon.awssdk.utils.async.SimplePublisher;
 
 @SdkInternalApi