Blink of an eye 

1. Initially used as a figure of speech to express astonishing speed.

2. But it can also be used as a form of sarcasm, in describing the amount of time it may take to complete a task in absolute contradictory or irony.

3. (Actual Speed) about 300-400 milliseconds.

A conversation between husband and wife.

<p><i>Husband: Honey! You forgot my suit at the dry cleaners. Now what am I going to wear?
Wife: I can go pick it up now if you'd like.
Husband: Maybe, but what if you don't make it back in time?
Wife: Don't worry, I'll be back in the blink of an eye.</i>.</p>

Blink of an eye by That's A Neck December 4, 2014

in the blink of an eye 

Very fast, rapidly

On Wall Street the market can change in the blink of an eye.

in the blink of an eye by Empty! February 26, 2018