depends on JUnit, though it continues to work with all testing frameworks.
 *  Fix: `FormEncodingBuilder` is now consistent with browsers in which
    characters it escapes. Previously we weren’t percent-encoding commas,
    parens, and other characters.
 *  Fix: Relax `FormEncodingBuilder` to support building empty forms.
 *  Fix: Timeouts throw `SocketTimeoutException`, not `InterruptedIOException`.