RSA and Perl - how randomness is achieved?

Does anyone have an experience of generating RSA keys with Crypt::OpenSSL::RSA module? The documentation seems to be vague regarding how randomness is achieved. For example, is it mandatory to call

Crypt::OpenSSL::RSA->import_random_seed();

before every call to

Crypt::OpenSSL::RSA->generate_key

or maybe calling import_random_seed once is enough even with multiple subsequent calls to generate_key?

And what about Crypt::OpenSSL::Random::random_seed($good_entropy)? It's said to be not necessary if there is /dev/random, but what if it's Windows?