keras/src/layers/preprocessing/text_vectorization.py/TextVectorization/compute_output_spec
class TextVectorization:    def compute_output_spec(self, inputs):
        output_shape = self.compute_output_shape(inputs.shape)
        if self._output_mode == "int":
            output_dtype = "int64"
        else:
            output_dtype = backend.floatx()
        return backend.KerasTensor(output_shape, dtype=output_dtype)