@Override
    public void normal(final Empty request, final StreamObserver<SomeType> responseObserver) {
        // Simulate processing time
        assertDoesNotThrow(this::sleep);
        responseObserver.onNext(SomeType.getDefaultInstance());
        responseObserver.onCompleted();
    }
Waits until all request have started processing on the server.
tests/src/test/java/net/devh/boot/grpc/test/server/WaitingTestService.java