ResponseDispatcher completeInput() {
            assertNotFailed();
            chunks.add(completionChunk);
            scheduleNextChunk();
            return this;
        }
Indicates that the input is completed and the currently enqueued response chunks are all that
remain to be scheduled for dispatch to the client.
grpc/src/test/java/com/linecorp/armeria/internal/common/grpc/TestServiceImpl.java