static long EmitMapper_List(int mappingsCount)
{
var list = new List<B2>();
for (var i = 0; i < mappingsCount; i++)
list.Add(new B2());
var sw = new Stopwatch();
sw.Start();
var mapper = ObjectMapperManager.DefaultInstance.GetMapper<B2, A2>(
new DefaultMapConfig().NullSubstitution<decimal?, int>(state => 42)
);
var dest = new List<A2>(list.Count);
foreach (var item in list)
dest.Add(mapper.Map(item));
sw.Stop();
return sw.ElapsedMilliseconds;
}