private Request<CopySnapshotRequest> generateRequestForPresigning(
            String sourceSnapshotId, String sourceRegion,
            String destinationRegion) {

        CopySnapshotRequest copySnapshotRequest = new CopySnapshotRequest()
                .withSourceSnapshotId(sourceSnapshotId)
                .withSourceRegion(sourceRegion)
                .withDestinationRegion(destinationRegion);

        return new CopySnapshotRequestMarshaller()
                .marshall(copySnapshotRequest);

    }
Generates a Request object for the pre-signed URL.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/transform/GeneratePreSignUrlRequestHandler.java