Codegen Attributes (#1299) * Initial tests for static call wrap * Finally sort of got somewhere... bit of a nightmare to debug this right now. Allow multiple CodeGenAttribute. Remove from ClientRpc and add some tests locally instead * Support CodeGenType.Instance with CodeGenType.WrapCall * Added first version of WrapSet/WrapGet * Unit test stubs * Don't pass value for get accessor.. * Cast to original return type in get accessor when wrapping * Tests build * Let CodeGenType.WrapCall proxies return their own values. They can simple do "return resume();" if they wanna keep intended behavior, so we can also wrap methods that don't just return void * Fixed a bug with static set/get wrap codegen not passing correct method name. Now support also adding [CodeGen] attributes directly to a method or property bypassing an attribute alias, these don't require setting the Instance/Static flags. * Use nameof where possible * Fixed tests for WrapSet/WrapGet * Improve documentation * Improve docs for CodeGenAttribute * More documentation * Fixed logic in WrapSet * Added method validation. Compiler will let you know what methods you're missing when using CodeGen and what types, return types etc they need * Add some extra tests * Only allow CodeGen on custom attributes. Tidy up. CallbackName for CodeGenType.Static is the actual fully qualified name of static method to call * Auto generate backing fields for properties. Pass current value in WrapGet callbacks. Set backing field before calling WrapSet callbacks. Update method validation error prints appropriately * Fixed ValidatePropertyCallback * Can now propertly wrap setters/getters. Setter callback passes Action<T> you can call to run default behavior * Fix error if value statement empty * Update tests * Fix TestWrapSet * Run WrapSet and WrapGet if both are specified. When passing to static callback always pass propertyName or methodName as fully qualified name. * Support type argument for return type and Func param * Nicer error when can't find type to invoke on for passed callback name * CodeGeneratorFlags/CodeGeneratorAttribute renaming * Update tests * WrapPropertySet, WrapPropertyGet, WrapMethod * Fix tests + fix issues with props that only have set; or get; * No need to wrap getValue() body in {} as already have them * Use SemanticModel.LookupSymbols to find and validate methods taking inheritance into account * Remove leftover test code