asp.net web api: action filter attribute is thread-safe by default?

Question

Can some one confirm me that asp.net web api action filters are singleton/instance based by default? In asp.net core, I observed that it has one instance by default and the method is as per request-based. I am not sure on wweb.api action filters. Sorry if this question sounds silly.

using System.Web.Http.Filters;
namespace SampleApp.Attributes
{
    public class CustomAttribute: Attribute, IActionFilter
    {
         public CustomAttribute()
         {
          // resolves dependencies here
         }

         public Task<HttpResponseMessage> ExecuteActionFilterAsync(HttpActionContext actionContext,
            CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
         {
              // some code goes here with some update operations in sql server stored procedure level
         }
    }          
}

Answer 1

As it states in the Microsoft documentation for filters (https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-6.0#thread-safety):

When passing an instance of a filter into Add, instead of its Type, the filter is a singleton and is not thread-safe.

If you're registering the filter type (rather than an instance), the framework will indeed create a new instance of the filter per request.