private val configuredLoggers = CopyOnWriteArraySet<Logger>()

  private val knownLoggers =
    LinkedHashMap<String, String>()
      .apply {
        val packageName = OkHttpClient::class.java.`package`?.name

        if (packageName != null) {
          this[packageName] = "OkHttp"
        }

        this[OkHttpClient::class.java.name] = "okhttp.OkHttpClient"
        this[Http2::class.java.name] = "okhttp.Http2"

to which the file belongs.
</p>

<pre class="ebnf">
PackageClause = "package" PackageName .
PackageName   = identifier .
</pre>

<p>
The PackageName must not be the <a href="#Blank_identifier">blank identifier</a>.
</p>

<pre>
package math
</pre>

<p>
A set of files sharing the same PackageName form the implementation of a package.