*   `tf.nn.embedding_lookup_sparse`

    *   Optimized this function for some cases by fusing internal operations.

*   `tf.saved_model.SaveOptions`

'mlir_module' is a serialized MLIR module with a `main` function that contains
target computation.
'dynamic_shapes' contains dynamic shapes of arguments whose shapes were not
known statically at TPUReplication rewrite time.
'metadata' is a serialized TPUCompileMetadataProto describing the shapes and
types of the inputs to the computation, as well as a mapping onto the TPU pod
topology.