@Override
                                       public void applyRequestMetadata(RequestInfo requestInfo,
                                                                        Executor appExecutor,
                                                                        MetadataApplier applier) {
                                           applier.fail(Status.FAILED_PRECONDITION);
                                       }
Must be at least {@link #unaryPayloadLength()}, plus some to account for encoding overhead.
grpc/src/test/java/com/linecorp/armeria/client/grpc/GrpcClientTest.java