Returns the (possibly negative) integer represented by the four bytes at
byteOffset in this object, in two's complement binary
The return value will be between -231 and 231 - 1, inclusive.
Throws RangeError if
byteOffset is negative, or
byteOffset + 4 is greater than the length of this object.
int getInt32(int byteOffset, [Endian endian = Endian.big]);