public Optional<Output<String>> key() {
        return Optional.ofNullable(this.key);
    }
@return Key is the taint key that the toleration applies to. Empty means match all taint keys. If the key is empty, operator must be Exists; this combination means to match all values and all keys. Must be a label name.
sdk/java/src/main/java/com/pulumi/kubernetes/resource/v1alpha3/inputs/DeviceTolerationPatchArgs.java