Who is Trudolyubov and Ferfichkin from Notes from the Underground and what is their importance?

Trudolyubov and Ferfichkin are two friends of Simonov's who plan the farewell dinner for Zverkov. They become embroiled in a heated argument with the writer and go so far as to say that he should never have invited himself and that he should leave. They clearly don't like the writer.