File read and parsing in kotlin

sample.kt

/**
 * Created by rane on 21/11/17.
 */
import java.io.File
import java.io.BufferedReader
import java.util.Date
import khronos.*

fun main(args: Array<String>) {
    val bufferedReader = File("/home/rane/tmp/datafile").bufferedReader()
    val lineList = mutableListOf<String>()

    //Data format 10.50.50.188 20/Nov/2017:06:46:42

    var data = mutableListOf<Pair<String, Date>>();
    bufferedReader.useLines { lines -> lines.forEach { lineList.add(it) } }
    println("Total records: ${lineList.count()}")

    lineList.forEach {
        var dt:String = it.split(" ")[1]
        data.add(Pair(it.split(" ")[0], dt.toDate("dd/MMM/yyyy:HH:mm:ss")));
    }

    var perMinCluster = mutableMapOf<String, MutableList<Pair<String, Date>>>()
    data.filterNotNull().forEach {
        var dt:String = it.second.toString("dd/MMM/YYYY:HH:mm")
        if(perMinCluster.containsKey(dt)) {
            perMinCluster.get(dt)?.apply {
                add(it)
            }
        } else {
            perMinCluster.put(dt, mutableListOf(it))
        }
        if(perMinCluster.count() % 10000 == 0) {
            println("Evaluated records: ${perMinCluster.count()}")
        }
    }
    println("Created perMinCluster: ${perMinCluster.count()}")

    var perMinuteCount = mutableListOf<Pair<String, Int>>()
    for((k, v) in perMinCluster) {
        perMinuteCount.add(Pair(k, v.count()))
    }
    println("Create perMinCount: ${perMinuteCount.count()}")

    var perMinAverage = (perMinuteCount.map {
        it.second
    }.sum()) / perMinuteCount.count()
    println("perMinAverage is $perMinAverage")

    var offenders = perMinuteCount.filter {
        it.second > perMinAverage * 5
    }

    offenders.forEach {
        println("${it.first} : ${it.second}")
    }
}