Remove Serde

src/types.rs

@@ -1,11 +1,7 @@
 //! Core types for the optimizer library.
 
-#[cfg(feature = "serde")]
-use serde::{Deserialize, Serialize};
-
 /// The direction of optimization.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum Direction {
     /// Minimize the objective value.
     Minimize,
@@ -15,7 +11,6 @@ pub enum Direction {
 
 /// The state of a trial in its lifecycle.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum TrialState {
     /// The trial is currently running.
     Running,