@Deprecated
    @Override
    protected IReadWriteStream<ApiRequest> requestDataHandler(ApiRequest request,
            IPolicyContext context, CachingConfig policyConfiguration) {
        // No need to handle the request stream (e.g. POST body)
        return null;
    }
@see io.apiman.gateway.engine.policies.AbstractMappedDataPolicy#requestDataHandler(io.apiman.gateway.engine.beans.ApiRequest, io.apiman.gateway.engine.policy.IPolicyContext, java.lang.Object)
gateway/engine/policies/src/main/java/io/apiman/gateway/engine/policies/CachingPolicy.java