code: @SuppressWarnings("unchecked")
      public final FluentModelImplT withTag(String key, String value) {
          if (this.inner().getTags() == null) {
              this.inner().withTags(new HashMap<String, String>());
          }
          this.inner().getTags().put(key, value);
          return (FluentModelImplT) this;
      }
docs: Adds a tag to the resource.
  @param key the key for the tag
  @param value the value for the tag
  @return the next stage of the definition/update