title: What is the difference between traceId and requestId in tracing?
body: <p>I am developing with microservices oriented architecture and want to trace. I was googling and I found that istio for example has the fallowing headers:</p>
  
  <ul>
  <li>x-request-id </li>
  <li>x-b3-traceid</li>
  <li>x-b3-spanid</li>
  <li>x-b3-parentspanid</li>
  <li>x-b3-sampled</li>
  <li>x-b3-flags</li>
  <li>x-ot-span-context</li>
  </ul>
  
  <p>Mainly I want to know the differences between <code>x-request-id</code> and <code>x-b3-traceid</code>, but ok if someone could share the others headers</p>