async _poll () {
    this._logger.info(`running poll on the secret ${this._namespace}/${this._name}`)

    try {
      await this._upsertKubernetesSecret()
      await this._updateStatus('SUCCESS')

      this._metrics.observeSync({
        name: this._name,
        namespace: this._namespace,
        backend: this._spec.backendType,
        status: 'success'
      })
    } catch (err) {
      this._logger.error(err, `failure while polling the secret ${this._namespace}/${this._name}`)
      await this._updateStatus(`ERROR, ${err.message}`)

      this._metrics.observeSync({
        name: this._name,
        namespace: this._namespace,
        backend: this._spec.backendType,
        status: 'error'
      })
    }
  }
Poll Kubernetes secrets.
@returns {Promise} Promise object that always resolves.