* Sets the level and returns this.
     *
     * This was deprecated in OkHttp 4.0 in favor of the [level] val. In OkHttp 4.3 it is
     * un-deprecated because Java callers can't chain when assigning Kotlin vals. (The getter remains
     * deprecated).
     */
    fun setLevel(level: Level) =
      apply {
        this.level = level
      }

    @JvmName("-deprecated_level")
    @Deprecated(

    This allows customization without the drawbacks of separate connection
    pools.

 *  **OkHttpClient is now stateless.** In the 2.x API `OkHttpClient` had getters
    and setters. Internally each request was forced to make its own complete
    snapshot of the `OkHttpClient` instance to defend against racy configuration

  AnnotationTarget.PROPERTY,
  AnnotationTarget.FIELD,
  AnnotationTarget.LOCAL_VARIABLE,
  AnnotationTarget.VALUE_PARAMETER,
  AnnotationTarget.CONSTRUCTOR,
  AnnotationTarget.FUNCTION,
  AnnotationTarget.PROPERTY_GETTER,
  AnnotationTarget.PROPERTY_SETTER,
  AnnotationTarget.TYPEALIAS,
)
@RequiresOptIn(level = RequiresOptIn.Level.ERROR)

in a future release! If you’re skipping releases, it’ll be much easier if you upgrade to OkHttp 4.0
as an intermediate step.

#### Vars and Vals

Java doesn’t have language support for properties so developers make do with getters and setters.
Kotlin does have properties and we take advantage of them in OkHttp.

 * **Address**: certificatePinner, connectionSpecs, dns, hostnameVerifier, protocols, proxy,