title: Unresolved reference: async in Kotlin in 1.3
body: <p>I have multi module kotlin gradle project in github <a href="https://github.com/rajcspsg/coroutines-demo/blob/introducing-coroutines/introducing-coroutines/" rel="noreferrer">here</a>.</p>
  
  <p>One of my sub project introducing-coroutines with build file build.gradle.kts file is <a href="https://github.com/rajcspsg/coroutines-demo/blob/introducing-coroutines/introducing-coroutines/build.gradle.kts" rel="noreferrer">here</a></p>
  
  <p>The contents of build.gradle.kts is -</p>
  
  <pre><code>    import org.jetbrains.kotlin.gradle.dsl.Coroutines
      import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
  
      plugins {
          java
          kotlin("jvm") version "1.3.11"
      }
  
      group = "chapter2"
      version = "1.0-SNAPSHOT"
  
      repositories {
          mavenCentral()
      }
  
      dependencies {
          compile(kotlin("stdlib-jdk8"))
          compile("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.1.0")
          testCompile("junit", "junit", "4.12")
      }
  
      configure&lt;JavaPluginConvention&gt; {
          sourceCompatibility = JavaVersion.VERSION_1_8
          targetCompatibility = JavaVersion.VERSION_1_8
      }
  
      tasks.withType&lt;KotlinCompile&gt; {
          kotlinOptions.jvmTarget = "1.8"
      }
  
      kotlin {
          experimental {
              coroutines   = Coroutines.ENABLE
          }
      }
  </code></pre>
  
  <p>I'm trying to create my first coroutine program from this <a href="https://github.com/rajcspsg/coroutines-demo/blob/introducing-coroutines/introducing-coroutines/src/main/kotlin/SumUsingCoroutines.kt" rel="noreferrer">link</a>.     </p>
  
  <pre><code>import kotlinx.coroutines.*
  import kotlinx.coroutines.async
  import kotlin.system.*
  import kotlin.system.measureTimeMillis
  
  suspend  fun computecr(array: IntArray, low: Int, high: Int): Long {
      return if (high - low &lt;= SEQUENTIAL_THRESHOLD) {
          (low until high)
                  .map { array[it].toLong() }
                  .sum()
      } else {
          val mid = low + (high - low) / 2
          val left = async { computecr(array, low, mid) }
          val right = compute(array, mid, high)
          return left.await() + right
      }
  }
  </code></pre>
  
  <p>When I compile the program I get the below error -</p>
  
  <pre><code>e: /Users/rajkumar.natarajan/Documents/Coding/coroutines-demo/introducing-coroutines/src/main/kotlin/SumUsingCoroutines.kt: (15, 20): Unresolved reference: async
  &gt; Task :introducing-coroutines:compileKotlin FAILED
  
  FAILURE: Build failed with an exception.
  </code></pre>
  
  <p>I can import <code>import kotlinx.coroutines.async</code> without any issue but not sure why I'm getting this error.</p>
  
  <p><a href="https://i.stack.imgur.com/GsQuc.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/GsQuc.jpg" alt="enter image description here"></a></p>
  
  <p>I have already verified similar issue <a href="https://stackoverflow.com/questions/44354355/unresolved-reference-async-in-kotlin">here</a> and added <code>anko-commons</code> dependency <a href="https://github.com/rajcspsg/coroutines-demo/blob/introducing-coroutines/introducing-coroutines/build.gradle.kts#L18" rel="noreferrer">here</a></p>
  
  <p>How can I resolve this error?</p>