title: Why hikari connection pool uses only 1 or 2 connections when receiving simultaeous multiple request?
body: <p>Hikari Pool looks like using only 1 or 2 connections in many connections in pool. I don't know why?</p>
  
  <p>Our service use hikari connection pool on starting my service.
  maximumPoolSize 50
  connectTimeout 3000</p>
  
  <p>and I sent 100 request to our service from jmeter and monitor mysql process list.
  mysql process is made 100 process.
  But only using 2 connections used. this others is sleeping.
  why connection pool use only 2 ?
  Is there any configuration in Hikari pool?</p>