Add `delegate::increment_async()` because it comes up fairly frequently.
Add `delegate::increment_async()` because it comes up fairly frequently.

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