flushToPipeSync(payload) {
    try {
      fs.writeFileSync(this.pipePath, payload)
      return true
    } catch (e) {
      logger.warn('Error attempting to write to pipe, falling back to stdout', e)
      return false
    }
  }
Writes payload to pipe

@param {string} payload serialized stringified-JSON payload to flush
@returns {boolean} whether or not flush was successful