#### Problem

...

#### Steps to replicate

Provide example config and message

#### Expected Behavior

...

#### Your environment

* OS version
* paste result of ``fluentd --version`` or ``td-agent --version``
* plugin version
  * paste boot log of fluentd or td-agent
  * paste result of ``fluent-gem list``, ``td-agent-gem list`` or your Gemfile.lock
