As Fast as a What?

On the way home from school Friday, D2 begged me to go to the local copy store. I know it is an unusual request for a second-grader. However, let me explain that it is not because she had any plans to increase the demand for the merciless death of helpless trees. It is the 25-cent gumball machine in the front corner by the window that continues to attract her fancy.
Now when I say "begged" you need to understand the intensity with which she petitioned this favor. From the time she climbed in the Yukon, while we waited for D1 and S2, and then for friend of D1, and then friend of S2, and for friend of S2's scooter, and for all backpacks and arms and legs to be safely stowed inside the vehicle, and then while we drove out of the school parking lot, and veered right down the first street, and then took a left turn down the next street, she did not stop pleading, "Can we go to Copy Right, please, please, please, please, please, please can we go to Copy Right, please, please, please, please, please." This she repeated incessantly.
Finally, I could not take the repetition anymore, not to mention the fact that her constant jabber was making it difficult to focus on the AM Talk Radio commentary screeching over my car speakers. So I momentarily turned down the volume, and spoke to D2 very calmly yet firmly, "We are not going to Copy Right. No matter how many times you ask, that is my final answer and it will not change at all today." D2 paused and then replied in a solemn voice, "But, Mom. I'll be as fast as a chicken. I promise."