public <T extends AmazonWebServiceRequest> T withRequestCredentialsProvider(final AWSCredentialsProvider credentialsProvider) {
        setRequestCredentialsProvider(credentialsProvider);
        @SuppressWarnings("unchecked")
        T t = (T) this;
        return t;
    }
Sets the optional credentials provider to use for this request, overriding the default credentials
provider at the client level.

@param credentialsProvider
           The optional AWS security credentials provider to use for this request, overriding the
           default credentials provider at the client level.
@return A reference to this updated object so that method calls can be chained together.
aws-java-sdk-core/src/main/java/com/amazonaws/AmazonWebServiceRequest.java