How an early Type XXI could accelerate Allied ASW

What changes if Germany develops the Type XXI submarine ten years early?

It prompts a much earlier Allied ASW race, but Germany pays for the acceleration by diverting research and development from other weapons.

An operational Type XXI in the early 1930s would attract close attention and intensive foreign ASW testing. The response first considers ahead-throwing weapons, then settles on earlier Squid development as a plausible result. Homing torpedoes are another possibility. Germany would also have to replace years of accumulated domestic and foreign research with a much larger research effort. More researchers, facilities and tests would consume resources otherwise available to other naval projects.