ComInterfaceGenerator.Initialize does more work than necessary setting up incremental steps and calculating some information before any GeneratedComInterfaceAttributes are found. We should move some of this processing to within the pipeline, only once we've found a GeneratedComInterfaceAttribute. We also should think about what level of granularity we need for each incremental step. There is some overhead to each incremental Select, and we make liberal use of it with small operations.