Implement delegate_read using delegate_call and test.
Implement delegate_read using delegate_call and test.

buaasun/grappa,alexfrolov/grappa,alexfrolov/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,uwsampa/grappa,buaasun/grappa,uwsampa/grappa,buaasun/grappa,buaasun/grappa,buaasun/grappa,buaasun/grappa,alexfrolov/grappa