parens, and other characters.
 *  Fix: Relax `FormEncodingBuilder` to support building empty forms.
 *  Fix: Timeouts throw `SocketTimeoutException`, not `InterruptedIOException`.
 *  Fix: Change `MockWebServer` to use the same logic as OkHttp when determining
    whether an HTTP request permits a body.
 *  Fix: `HttpUrl` now uses the canonical form for IPv6 addresses.

import assertk.assertions.isNull
import assertk.assertions.isTrue
import assertk.assertions.startsWith
import assertk.fail
import java.io.FileNotFoundException
import java.io.IOException
import java.io.InterruptedIOException
import java.net.CookieManager
import java.net.CookiePolicy
import java.net.HttpCookie
import java.net.HttpURLConnection
import java.net.InetAddress
import java.net.ProtocolException
import java.net.Proxy

 *  Fix: Reverse suppression of connect exceptions. When both a call and its retry fail, we now
    throw the initial exception which is most likely to be actionable.
 *  Fix: Retain interrupted state when throwing `InterruptedIOException`. A single interrupt should
    now be sufficient to break out an in-flight OkHttp call.
 *  Fix: Don't drop a call to `EventListener.callEnd()` when the response body is consumed inside an
    interceptor.