How to deactivate feature from site collecion programmatically?

How to deactivate feature from site collection? I am trying the code below but got this error:

Updates are currently disallowed on GET requests. To allow updates on
a GET, set the ‘AllowUnsafeUpdates’ property on SPWeb”.

private void DeactivateProvisioningFeature()
        {
            using (SPSite site = new SPSite(SPContext.Current.Site.Url))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    web.AllowUnsafeUpdates = true;
                    site.AllowUnsafeUpdates = true;

                    var feature = site.Features.SingleOrDefault(sf => sf.DefinitionId == new Guid("464b78de-c14e-4c88-bd52-00136fc899f4")); // find delegate control provisioning feature
                    if (feature != null) //if feature is activated
                    {
                        site.Features.Remove(feature.DefinitionId, true); //deactivate feature
                    }

                    web.Update();

                    site.AllowUnsafeUpdates = false;
                    web.AllowUnsafeUpdates = false;
                }
            }
        }