title: Kotlin : Function invocation 'buffer()' expected
body: <p>I write an OkHttp Log Interceptor using <code>responseBody.source().buffer</code>.
  It works fine when I run the app with Android Studio, but it fails to compile when I try to build an APK.</p>
  <pre><code>e: F:\source\ZZCloud\lib.frame\src\main\java\com\fine\mps\net\FineHttpLogger.kt: (117, 37): Function invocation 'buffer()' expected
  </code></pre>
  <p>The buffer code:</p>
  <pre class="lang-kotlin prettyprint-override"><code>interface BufferedSource : Source, ReadableByteChannel {
    /** Returns this source's internal buffer. */
    @Deprecated(
      message = &quot;moved to val: use getBuffer() instead&quot;,
      replaceWith = ReplaceWith(expression = &quot;buffer&quot;),
      level = DeprecationLevel.WARNING)
    fun buffer(): Buffer
  
   /** This source's internal buffer. */
    val buffer: Buffer
  }
  </code></pre>
  <p>My code at FineHttpLogger.kt: (117, 37):</p>
  <pre class="lang-kotlin prettyprint-override"><code>val source = responseBody.source()
  var buffer = source.buffer
  </code></pre>