@JRubyMethod(meta = true)
public static IRubyObject for_fd(ThreadContext context, IRubyObject _klass, IRubyObject _fileno) {
Ruby runtime = context.runtime;
int fileno = (int) _fileno.convertToInteger().getLongValue();
RubyClass klass = (RubyClass) _klass;
ChannelDescriptor descriptor =
ChannelDescriptor.getDescriptorByFileno(runtime.getFilenoExtMap(fileno));
RubyBasicSocket basicSocket = (RubyBasicSocket) klass.getAllocator().allocate(runtime, klass);
basicSocket.initSocket(runtime, descriptor);
return basicSocket;
}