Check if a method is invoked inside another method in all execution paths by Roslyn

Question

Using Roslyn, how can I check the body of a method to determine whether another method is always invoked before returning? For example, in an OWIN middleware, I want to check if the next method is called in all execution paths.

try
{
    await next();
}
catch
{
   Console.WriteLine("Error"); // the next() is not invoked
}

or

if(condition)
   return; // The next method invocation is ignored

await next();