code: public static Tag create(TagKey key, TagValue value, TagMetadata tagMetadata) {
      return new AutoValue_Tag(key, value, tagMetadata);
    }
docs: Creates a {@code Tag} from the given key, value and metadata.
  
  @param key the tag key.
  @param value the tag value.
  @param tagMetadata the tag metadata.
  @return a {@code Tag}.
  @since 0.20