- replaces #toLowerCase() with #toLowerCase(Locale).
  #toLowerCase() without a Locale may lead to unexpected
  results in JVM with Turkish locale (s. JavaDocs of
  String#toLowerCase()).
XNIO-210 SSL awaitReadable() always waits on the underlying channel even if there is data in the unwrap buffer
Hold the buffer lock in awaitReadable()
Do not recurse when old locking is in effect
Improve error detection and logging