Added the FunctionRegistry, which allows referencing of Function spec…

…s during the scope of a single request/response transaction.

Sources/CleverBird/chat/FunctionRegistry.swift

@@ -0,0 +1,24 @@
+//  Created by B.T. Franklin on 6/16/23
+
+class FunctionRegistry {
+
+    static let shared: FunctionRegistry = FunctionRegistry()
+
+    private var functionsByName: [String:Function] = [:]
+
+    private init() {
+        // Private to prevent non-singleton use
+    }
+
+    func setFunctions(_ functions: [Function]) {
+        functions.forEach { self.functionsByName[$0.name] = $0 }
+    }
+
+    func clearFunctions() {
+        self.functionsByName.removeAll()
+    }
+
+    func getFunction(withName name: String) -> Function? {
+        functionsByName[name]
+    }
+}