void completeDelayedChannelClose(long currentTimeNanos) {
        if (delayedClosingChannels == null)
            return;

        while (!delayedClosingChannels.isEmpty()) {
            DelayedAuthenticationFailureClose delayedClose = delayedClosingChannels.values().iterator().next();
            if (!delayedClose.tryClose(currentTimeNanos))
                break;
        }
    }
handle any ready I/O on a set of selection keys
@param selectionKeys set of keys to handle
@param isImmediatelyConnected true if running over a set of keys for just-connected sockets
@param currentTimeNanos time at which set of keys was determined
clients/src/main/java/org/apache/kafka/common/network/Selector.java