num properties: 8
delay: 10
endDelay: 20
fill: forwards
iterationStart: 30
iterations: 40
duration: 50
direction: alternate-reverse
easing: linear
updateTiming() throws if it receives a negative iterationStart value
updateTiming() throws if it receives a negative iterations value
updateTiming() throws if it receives a NaN iterations value
updateTiming() throws if it receives a negative duration value
updateTiming() throws if it receives a NaN duration value
updateTiming() throws if it receives an invalid easing function value
