RegexRedux in Kotlin with coroutines

AsyncRegex.kt

import kotlinx.coroutines.*

import java.io.File

fun main() = runBlocking {
    val start = System.nanoTime()
    val input = File("file_path.txt").readText(Charsets.UTF_8)
    val sequence = ">.*\n|\n".toRegex().replace(input, "")

    val replacements = listOf(
        "tHa[Nt]" to "<4>",
        "aND|caN|Ha[DS]|WaS" to "<3>",
        "a[NSt]|BY" to "<2>",
        "<[^>]*>" to "|",
        "\\|[^|][^|]*\\|" to "-"
    )

    val reps = GlobalScope.launch {
        replacements.fold(sequence) {
                buffer,
                (pattern, replacement) -> pattern.toRegex().replace(buffer, replacement)
        }.let {
            println(it.length)
        }
    }

    val variants = listOf(
        "agggtaaa|tttaccct",
        "[cgt]gggtaaa|tttaccc[acg]",
        "a[act]ggtaaa|tttacc[agt]t",
        "ag[act]gtaaa|tttac[agt]ct",
        "agg[act]taaa|ttta[agt]cct",
        "aggg[acg]aaa|ttt[cgt]ccct",
        "agggt[cgt]aa|tt[acg]accct",
        "agggta[cgt]a|t[acg]taccct",
        "agggtaa[cgt]|[acg]ttaccct"
    )

    val vars = GlobalScope.launch {
        variants.map {
            async {
                it to it.toRegex().findAll(sequence).count()
            }
        }
        .map { it.await() }
        .forEach { (k, v) -> println("$k $v") }

        println(
         """

        ${input.length}
        ${sequence.length}
        """.trimIndent())
    }

    vars.join()
    reps.join()
    println("elapsed: ${(System.nanoTime().toDouble() - start.toDouble()) / 1E9} secs")
}