add has_step

Author: SebastianM-C

docs/src/interfaces/Algorithms.md

@@ -36,6 +36,7 @@ SciMLBase.isdiscrete
 SciMLBase.forwarddiffs_model
 SciMLBase.forwarddiffs_model_time
 SciMLBase.has_init
+SciMLBase.has_step
 ```
 
 ### Abstract SciML Algorithms

src/SciMLBase.jl

@@ -935,5 +935,6 @@ export ODEAliasSpecifier, LinearAliasSpecifier
 # Public traits
 
 @public has_init
+@public has_step
 
 end

src/alg_traits.jl

@@ -308,6 +308,14 @@ supports_opt_cache_interface(alg) = false
 """
     $(TYPEDSIGNATURES)
 
-Trait for specifying whether the passed algorithm supports `init`.
+Trait for specifying whether the passed algorithm supports `init`. Any `init`ed object can `solve!`.
 """
 has_init(a::AbstractSciMLAlgorithm) = false
+
+"""
+    $(TYPEDSIGNATURES)
+
+Trait for specifying whether the passed algorithm supports `step!`, specifying a more direct control over the internal solver process.
+See https://docs.sciml.ai/SciMLBase/stable/interfaces/Init_Solve/#init-and-the-Iterator-Interface for more details.
+"""
+has_step(a::AbstractSciMLAlgorithm) = false