How do you apply a .net attribute to a return type

Question

How do I apply the MarshalAsAttribute to the return type of the code below?

public ISomething Foo()
{
    return new MyFoo();
}

Answer 1

According to http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.marshalasattribute.aspx:

[return: MarshalAs(<your marshal type>)]
public ISomething Foo()
{
    return new MyFoo();
}

Answer 2

[return:MarshalAs]
public ISomething Foo()
{
    return new MyFoo();
}