#if MONO using System;using System.Runtime;using System.Security; namespace System.Threading{    internal class CancellationCallbackInfo    {        internal readonly Action<object> Callback;        internal readonly object StateForCallback;        internal readonly SynchronizationContext TargetSyncContext;        internal readonly ExecutionContext TargetExecutionContext;        internal readonly CancellationTokenSource CancellationTokenSource;        [SecurityCritical]        private static ContextCallback s_executionContextCallback;         internal CancellationCallbackInfo(Action<object> callback, object stateForCallback, SynchronizationContext targetSyncContext, ExecutionContext targetExecutionContext, CancellationTokenSource cancellationTokenSource)        {            this.Callback = callback;            this.StateForCallback = stateForCallback;            this.TargetSyncContext = targetSyncContext;            this.TargetExecutionContext = targetExecutionContext;            this.CancellationTokenSource = cancellationTokenSource;        }        [SecuritySafeCritical]        internal void ExecuteCallback()        {            if (this.TargetExecutionContext != null)            {                ContextCallback contextCallback = CancellationCallbackInfo.s_executionContextCallback;                if (contextCallback == null)                {                    contextCallback = (CancellationCallbackInfo.s_executionContextCallback = new ContextCallback(CancellationCallbackInfo.ExecutionContextCallback));                }                ExecutionContext.Run(this.TargetExecutionContext, contextCallback, this);                return;            }            CancellationCallbackInfo.ExecutionContextCallback(this);        }        [SecurityCritical]        private static void ExecutionContextCallback(object obj)        {            CancellationCallbackInfo cancellationCallbackInfo = obj as CancellationCallbackInfo;            cancellationCallbackInfo.Callback(cancellationCallbackInfo.StateForCallback);        }    }} #endif