Leave a multicast group. Its behavior may be affected by
setInterface or
setNetworkInterface.
If there is a security manager, this method first calls its checkMulticast method with the mcastaddr argument as its argument.
@param mcastaddr is the multicast address to leave
@exception IOException if there is an error leavingor when the address is not a multicast address.
@exception SecurityException if a security manager exists and its checkMulticast method doesn't allow the operation.
@see SecurityManager#checkMulticast(InetAddress)