Why is Gatling pausing before sending Requests

Gatling (Open-Source)
1

Gatling 3.0.3 is pausing for 25 seconds before the injection.

I am using the Radius Plugin bpabdelkader/gatling-radius I’ve already developped to load test our Radius Server.

My sample Scenario is as follows:

import io.gatling.core.Predef._

import com.ngenia.radius.Predef._
import com.ngenia.radius.protocol._

class RadiusSimulation extends Simulation {

  implicit val radiusProtocol: RadiusProtocol = radius
    .host("10.20.30.40")
    .sharedKey("mySharedKey")
    .replyTimeout(100) // 100 ms

  val scn = scenario("Access Request")
    .feed(csv("data/dataFeeder.csv").circular)
    .exec(
      radius("Access Request")
        .username("${username}")
        .password("${password}")
        .properties(
          Map(
            "NAS-Identifier" -> "${NAS-Identifier}",
            "NAS-IP-Address" -> "${NAS-IP-Address}",
            "Calling-Station-Id" -> "${Calling-Station-Id}",
            "Called-Station-Id" -> "${Called-Station-Id}"
          ))
        .authenticate()
    )

  setUp(scn.inject(atOnceUsers(1000))).protocols(radiusProtocol)
}

Once launched, I can see 1000 users waiting for 25 sec before the Injection began

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17:15:26.944 [INFO ] i.g.c.s.w.ConsoleDataWriter - Initializing
17:15:26.944 [INFO ] i.g.c.s.w.LogFileDataWriter - Initializing
17:15:26.949 [INFO ] i.g.c.s.w.ConsoleDataWriter - Initialized
17:15:26.955 [INFO ] i.g.c.s.w.LogFileDataWriter - Initialized