UniTask/Assets/UniRx.Async/CompilerServices/AsyncMethodBuilderAttribute.cs

#if CSHARP_7_OR_LATER || (UNITY_2018_3_OR_NEWER && (NET_STANDARD_2_0 || NET_4_6))

#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
#pragma warning disable CS0436

namespace System.Runtime.CompilerServices
{
    internal sealed class AsyncMethodBuilderAttribute : Attribute
    {
        public Type BuilderType { get; }

        public AsyncMethodBuilderAttribute(Type builderType)
        {
            BuilderType = builderType;
        }
    }
}

#endif