[Obsolete("This method is no longer recommended to use.")] public void OldMethod() { //code here }
[Serializable] public class MyClass { //code here }
[Conditional("DEBUG")] public void DebugMethod() { //debug-only code here }The Mono.CSharp Attributes package library can be determined by the namespace, which is Mono.CSharp. The package can be installed using NuGet package manager in Visual Studio.