title: How to create a scala.concurrent.ExecutionContext
body: <p>How to create a <code>scala.concurrent.ExecutionContext</code> ?</p>
  
  <p>The documentation generally gives an overall summary and mentions the "default" implementation of <code>scala.concurrent.ExecutionContext.global</code>.</p>
  
  <p>Still, sometimes you have to create your personal E.C., without using <code>akka</code> and other such tools.</p>