public static V1BinaryAnnotation createString(String key, String value, Endpoint endpoint) {
    if (value == null) throw new NullPointerException("value == null");
    return new V1BinaryAnnotation(key, value, endpoint);
  }
Creates a tag annotation, which is the same as {@link Span#tags()} except duplicating the
endpoint.

<p>A special case is when the key is "lc" and value is empty: This substitutes for the {@link
Span#localEndpoint()}.
zipkin/src/main/java/zipkin2/v1/V1BinaryAnnotation.java