TensorList operations.
    *   `tf.custom_gradient` can now be applied to functions that accept nested
        structures of `tensors` as inputs (instead of just a list of tensors).
        Note that Python structures such as tuples and lists now won't be
        treated as tensors, so if you still want them to be treated that way,
        you need to wrap them with `tf.convert_to_tensor`.

### Structured logging

SIG Instrumentation standardized the structure of log messages and references to Kubernetes objects. Structured logging makes parsing, processing, storing, querying and analyzing logs easier. New methods in the klog library enforce log message structure.

### EndpointSlices are now enabled by default