emulMaskInit
emulMaskInit(ctx, rdLast, EV_READ, 1);
emulMaskInit(ctx, rdNext, EV_READ, 0);
emulMaskInit(ctx, wrLast, EV_WRITE, 1);
emulMaskInit(ctx, wrNext, EV_WRITE, 0);
emulMaskInit(ctx, exLast, EV_EXCEPT, 1);
emulMaskInit(ctx, exNext, EV_EXCEPT, 0);
emulMaskInit(ctx, nonblockBefore, EV_WASNONBLOCKING, 0);