Clarify documentation for Actor

actor.go

@@ -3,17 +3,29 @@ package camfish
 import "context"
 
 // Actor is a participant in the environment. All public methods on an actor
-// must be safe for concurrent use by multiple goroutines. Additionally, any
-// type which explicitly implements Actor should:
+// should be safe for concurrent use by multiple goroutines except for AddFlags,
+// Init, Configure, and ProcessConfig. Additionally, any type which explicitly
+// implements Actor should:
+//
 //   - Treat all public fields, values, indices, etc. as immutable
 //   - Satisfy Actor as a pointer, not a value
 //   - Not have a constructor
+//
+// The CAMFISH environment will use interfaces in this package to probe actors
+// for methods. If an actor is supposed to fulfill one of these interfaces, this
+// should be enforced at compile-time by assigning the actor to an anonymous
+// global variable of that interface type. For instance, this line will ensure
+// that SomeActor fulfills [Resettable]:
+//
+//   var _ camfish.Resettable = new(SomeActor)
 type Actor interface {
-	// Type returns the type name of the actor. The value returned from this
-	// is used to locate actors capable of performing a specific task, so it
-	// absolutely must return the same string every time. Actors implemented
-	// in packages besides this one (i.e. not camfish) must not return the
-	// string "cron".
+	// Type returns the "type name" of the actor. The value returned from
+	// this is used to locate actors capable of performing a specific task,
+	// so it absolutely must return the same string every time. It is
+	// usually best to have this be unique to each actor. Actors implemented
+	// in packages other than this one
+	// (git.tebibyte.media/sashakoshka/camfish) must not return the string
+	// "cron".
 	Type() string
 }