feat: Begins more work on async integration

Sources/Models/TrackedChanges.swift

@@ -1,11 +1,20 @@
-
+/// A property wrapper that tracks changes of a property.
+///
+/// This allows values to only publish changes if they have changed since the
+/// last time they were recieved.
 @propertyWrapper
 public struct TrackedChanges<Value> {
-  
+
+  /// The current tracking state.
   private var tracking: TrackingState
+
+  /// The current wrapped value.
   private var value: Value
+
+  /// Used to check if a new value is equal to an old value.
   private var isEqual: (Value, Value) -> Bool
-  
+
+  /// Access to the underlying property that we are wrapping.
   public var wrappedValue: Value {
     get { value }
     set {
@@ -16,7 +25,13 @@ public struct TrackedChanges<Value> {
       tracking = .needsProcessed
     }
   }
-  
+
+  /// Create a new property that tracks it's changes.
+  ///
+  /// - Parameters:
+  ///   - wrappedValue: The value that we are wrapping.
+  ///   - needsProcessed: Whether this value needs processed (default = false).
+  ///   - isEqual: Method to compare old values against new values.
   public init(
     wrappedValue: Value,
     needsProcessed: Bool = false,
@@ -26,12 +41,18 @@ public struct TrackedChanges<Value> {
     self.tracking = needsProcessed ? .needsProcessed : .hasProcessed
     self.isEqual = isEqual
   }
-  
+
+  /// Represents whether a wrapped value has changed and needs processed or not.
   enum TrackingState {
+
+    /// The state when nothing has changed and we've already processed the current value.
     case hasProcessed
+
+    /// The state when the value has changed and has not been processed yet.
     case needsProcessed
   }
-  
+
+  /// Check whether the value needs processed.
   public var needsProcessed: Bool {
     get { tracking == .needsProcessed }
     set {
@@ -42,7 +63,7 @@ public struct TrackedChanges<Value> {
       }
     }
   }
-  
+
   public var projectedValue: Self {
     get { self }
     set { self = newValue }
@@ -54,7 +75,12 @@ extension TrackedChanges: Equatable where Value: Equatable {
     lhs.wrappedValue == rhs.wrappedValue
       && lhs.needsProcessed == rhs.needsProcessed
   }
-  
+
+  /// Create a new property that tracks it's changes, using the default equality check.
+  ///
+  /// - Parameters:
+  ///   - wrappedValue: The value that we are wrapping.
+  ///   - needsProcessed: Whether this value needs processed (default = false).
   public init(
     wrappedValue: Value,
     needsProcessed: Bool = false