Tensorflow for Dart lang?
Not officially, although many community activities have begun to implement TensorFlow APIs using gRPC. Native bindings are less popular due to the complexities involved. Even the official C++ API is behind Python currently.
I would suggest first looking at JavaScript if you want to pursue Dart and TensorFlow, otherwise it's not likely you'll have a solution in the near future.
I've been working on a Swift API for TensorFlow, and utilizing the Go API, but even though these are two very popular languages, outside of Python, in the TensorFlow community, the complexity of building the APIs are proving difficult to overcome.