This interface is to be implemented that performs any kind of
measurement on a sequence, such as system delay, maximum
delay, makespan, robustness, etc.
Interface to be implemented by classes that calculate the minimum
separation time between two aircraft based on their weight class
and action type (departure, arrival, or arrival crossing).
Edge value strategy that simply sets the minimum separation times
as the edge weights, and does no further calculations before
returning those weights upon request.