feat: add support for save_discretes in integrator.opts

Author: AayushSabharwal

src/callbacks.jl

@@ -596,10 +596,12 @@ function apply_callback!(integrator,
 
         @inbounds if callback.save_positions[2]
             savevalues!(integrator, true)
-            if callback isa VectorContinuousCallback
-                SciMLBase.save_discretes!(integrator, callback, event_idx)
-            else
-                SciMLBase.save_discretes!(integrator, callback)
+            if isdefined(integrator.opts, :save_discretes) && integrator.opts.save_discretes
+                if callback isa VectorContinuousCallback
+                    SciMLBase.save_discretes!(integrator, callback, event_idx)
+                else
+                    SciMLBase.save_discretes!(integrator, callback)
+                end
             end
             saved_in_cb = true
         end
@@ -627,7 +629,9 @@ end
         end
         @inbounds if callback.save_positions[2]
             savevalues!(integrator, true)
-            SciMLBase.save_discretes!(integrator, callback)
+            if isdefined(integrator.opts, :save_discretes) && integrator.opts.save_discretes
+                SciMLBase.save_discretes!(integrator, callback)
+            end
             saved_in_cb = true
         end
     end