private static void writeLabel(final JsonGenerator jsonGenerator, final String labelName, final String labelValue) throws IOException {
        jsonGenerator.writeFieldName(labelName);
        jsonGenerator.writeStartArray();
        jsonGenerator.writeString(labelValue);
        jsonGenerator.writeEndArray();
    }
Helper method for writing a label. Starting in v4, the label is an array of String that is inside an object. Only
writes the array portion; that is, it assumes the object has already started.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphson/GraphSONSerializersV4.java