raw
Replace an unsigned base 2^32 digit of the integer. The index must be in range for the integer's representation, and the receiver must be mutable.
Parameters
index
The one-based, little-endian index of the digit to replace. It must be between 1 and the number of digits present.
value
The replacement base 2^32 digit as an Int. This does the same thing as rawSignedIntegerAtPut.