code: String decodeCString(ByteBuf buffer) throws IOException {
          int length = buffer.bytesBefore(BsonConstants.STRING_TERMINATION);
          if (length < 0)
              throw new IOException("string termination not found");
  
          String result = buffer.toString(buffer.readerIndex(), length, StandardCharsets.UTF_8);
          buffer.skipBytes(length + 1);
          return result;
      }
docs: default visibility for unit test