addAttribute(key, value) {
    const streamingValue = mapToStreamingType(value)
    if (streamingValue) {
      this[key] = streamingValue
      return true
    }

    return false
  }
Add a key/value pair to the attribute collection.
null/undefined values will be dropped.

Does not apply filtering/truncation.

@param {string} key Name of the attribute to be stored.
@param {string|boolean|number} value Value of the attribute to be stored.