code: public static Function<Client<RpcRequest, RpcResponse>, CircuitBreakerRpcClient>
      newPerHostAndMethodDecorator(Function<String, CircuitBreaker> factory,
                                   CircuitBreakerStrategyWithContent<RpcResponse> strategy) {
          return newDecorator(CircuitBreakerMapping.perHostAndMethod(factory), strategy);
      }
docs: Creates a new decorator that binds one {@link CircuitBreaker} per host and RPC method name with
  the specified {@link CircuitBreakerStrategy}.
  
  <p>Since {@link CircuitBreaker} is a unit of failure detection, don't reuse the same instance for
  unrelated services.
  
  @param factory a function that takes a host+method and creates a new {@link CircuitBreaker}