title: How log request and response body in Istio
body: <p>I'd like to log request and response body from incoming traffic to each my microservice. 
  Is it possible in Istio (Envoy) out-of-the-box? 
  I don't see body attribute for mapping in Mixer's EntryLog.
  Maybe it will be added in future version of Istio?</p>
  
  <p>Of course I can achieve this by implementing my own filter in microservise, but maybe there is better solution to achieve this.</p>