core.time Duration how to get units in double/float format?

[Borislav Kosharov via Digitalmars-d-learn]

Seeing that TickDuration is being deprecated and that I should 
use Duration instead, I faced a problem. I need to get total 
seconds like a float. Using .total!"seconds" returns a long and 
if the duration is less than 1 second I get 0. My question is 
whats the right way to do it. Because I saw that TickDuration has 
a to!("seconds", float) method, but Duration doesn't have one. I 
can convert Duration to TickDuration and call to but seeing that 
its deprecated makes me think there is a better way.