Returns the (possibly negative) integer represented by the eight bytes at the specified byteOffset in this object, in two's complement binary form.
Returns the (possibly negative) integer represented by the eight bytes at the specified byteOffset in this object, in two's complement binary form.
The return value will be between 2<sup>63</sup> and 2<sup>63</sup> - 1, inclusive.
Throws RangeError if byteOffset is negative, or
byteOffset + 8
is greater than the length of this object.