public static <T> void writeList(WriteBuffer.Writer<T> writer, List<T> value, WriteBuffer b) {
    b.writeByte('[');
    for (int i = 0, length = value.size(); i < length; ) {
      writer.write(value.get(i++), b);
      if (i < length) b.writeByte(',');
    }
    b.writeByte(']');
  }
Inability to encode is a programming bug.
zipkin/src/main/java/zipkin2/internal/JsonCodec.java