Even closer to get example "basic" up and running!

src/fitter.rs

@@ -4,7 +4,10 @@ pub use recursive::RecursiveFitter;
 
 pub trait Fitter {
     fn add_sample(&mut self, t: f64) -> usize;
+
     fn allocate(&mut self);
+    fn is_allocated(&self) -> bool;
+
     fn fit(&mut self);
 
     fn vs(&self, idx: usize) -> f64;