title: Receiving message multiple time for same event Server sent event
body: <p>I am working on a Web app to control some light using openHab API and using SSE but when the light goes on I received 3 message at the same time</p>
  
  <p>one with the value 100
  and the two other same message with the actual value of the light (ex 45)
  the value correspond to the % of the brightness of the light</p>
  
  <pre><code>eventSource.onmessage = (event: any) =&gt; {
        this.val = JSON.parse(JSON.parse(event.data).payload).value;
        console.log("new val " + this.val);
        slid.value = this.val;
        if(this.val &gt;= 1){
          this.light = true;
          button.checked= true;
        }
        else{
          this.light = false;
          button.checked = false;
        }
      };
  </code></pre>
  
  <p>the problem with that is that my progressbar that show where the light is goes to 100% then descend to the value it should and I would like to avoid that is there any thing to prevent the message or to update the value only for the last message received ?</p>
  
  <p>thanks.</p>