Specifies whether operations are executed synchronously or asynchronously.
TensorFlow can execute operations synchronously or asynchronously. If asynchronous execution is enabled, operations may return "non-ready" handles.
enable is set to None, an appropriate value will be picked
automatically. The value picked may change between TensorFlow releases.
enable: Whether operations should be dispatched synchronously. Valid values:
- None: sets the system default.
- True: executes each operation synchronously.
- False: executes each operation asynchronously.