docs: public void setLocale(Locale locale) {
          if (locale == null) {
              throw new IllegalArgumentException("locale must not be null.");
          }
  
          synchronized (mLock) {
              throwIfNotOpenLocked();
  
              final Locale oldLocale = mConfigurationLocked.locale;
              mConfigurationLocked.locale = locale;
              try {
                  mConnectionPoolLocked.reconfigure(mConfigurationLocked);
              } catch (RuntimeException ex) {
                  mConfigurationLocked.locale = oldLocale;
                  throw ex;
              }
          }
      }