Consider wrapping in return in an object

[Brennan1994]

McCormackScheme/McCormackScheme/McCormackScheme/McCormack.cs

Line 11 in cf6cf55

public static (double[], double[], double[]) Scheme(double[] depths, double[] velocities, double[] flows, int nx, double dx, double dt, double g, double manningsN, double bankSlope)

Wrapping the double arrays in an object with getters for the values would make it a little clearer what each return is. Also makes it possible to extend your returns without modifying this method signature. Like if you wanted to also calculate and return shear stress later.