public static boolean addSignal(final String signalName, final List<JRaftSignalHandler> handlers) {
        if (SIGNAL_ACCESSOR != null) {
            SIGNAL_ACCESSOR.addSignal(signalName, handlers);
            return true;
        }
        return false;
    }
Registers user signal handlers.

@param signalName a signal name
@param handlers   user signal handlers
@return true if support on current platform
jraft-core/src/main/java/com/alipay/sofa/jraft/util/SignalHelper.java