input: Write a function in C# that converts the given Python program to a C# program. The function should take two integer parameters `x` and `y` and return an integer. The Python program calculates the power of `x` raised to the `y` using recursion. If `y` is 0, the function should return 1. Otherwise, it should return `x` multiplied by the result of the same function called with `y-1`. The C# function should have the signature `public int Power(int x, int y)`.
  
  assert Power(2, 3)==8
  assert Power(5, 0)==1
  assert Power(10, 2)==100
  assert Power(0, 2)==0
  assert Power(3, 4)==81
output: def Power(x, y):
      if y == 0:
          return 1
      else:
          return x * Power(x, y - 1)