Type erasure and escape analysis are not entirely unrelated. If you have an array of pairs and store a pair into that array then the pair is considered to escape in Java because you're actually storing a pointer to your original pair. In C# that array can store a true array of pairs rather than an array of pointers to pairs. A pair you store gets copied into the array, so the original pair does not have to be considered to escape and can be stored on the stack and deallocated when the function exits.

Although C# does not have escape analysis, its value type vs reference type distinction serves roughly the same purpose, but under manual control of the programmer.