Insert JSON document into ElasticSearch using Elastic4s

InsertJson.scala

// Dependency: elastic4s
import java.util.Calendar

import com.sksamuel.elastic4s.ElasticDsl._
import com.sksamuel.elastic4s.source.StringDocumentSource
import com.sksamuel.elastic4s.{ElasticClient, ElasticsearchClientUri}
import org.elasticsearch.action.index.IndexResponse

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future
import scala.util.{Failure, Success}

object Elastic {
  println("Creating Elastic Connection")
  // todo (harit): ElasticSearch Configuration should be configurable
  val uri = ElasticsearchClientUri("elasticsearch://192.168.99.100:9300")
  val client = ElasticClient.remote(uri)

  def insert(monitorJson: String) = {
    client execute {
      index into "test" -> "events" doc StringDocumentSource(monitorJson)
    }
  }
}

object Test extends App {
  insertJson

  def insertJson: IndexedSeq[Unit] = {
    for (_ <- 1 to 100) yield {
      val today = Calendar.getInstance() getTimeInMillis
      val json: String = s"""{"time": ${today}}"""
      val insert: Future[IndexResponse] = Elastic.insert(json)
      insert onComplete {
        case Success(response) => println("inserted successfully: {}", response)
        case Failure(reason) => println("Insert failed: {}", reason)
      }
    }
  }
}

com.sksamuel.elastic4s.source.StringDocumentSource, source not resolved - please update the code or let me know how to resolve it

I think it is JsonDocumentSource with elastic4s 2.4.1