get restart time from open message error

in class GracefulCapabilityHandler method parseCapability.
final int flagBits = (buffer.getByte(0) >> RESTART_FLAGS_SIZE);
cb.setRestartFlags(new RestartFlags((flagBits & Byte.SIZE) != 0));

final int timer = ((buffer.readUnsignedByte() & TIMER_TOPBITS_MASK) << RESTART_FLAGS_SIZE) + buffer.readUnsignedByte();
cb.setRestartTime(timer);

get restart time ,high byte value must left shift one byte length.
in code ,only shift
private static final int RESTART_FLAGS_SIZE = 4;