NotNullWhenAttribute
Specifies that when a method returns ReturnValue, the parameter will not be null even if the corresponding type allows it.
namespace System.Diagnostics.CodeAnalysis
{
[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false)]
internal sealed class NotNullWhenAttribute : Attribute
{
public bool ReturnValue { get; }
public NotNullWhenAttribute(bool returnValue)
{
ReturnValue = returnValue;
}
}
}