int getUint64(int byteOffset, [ Endianness endian = Endianness.BIG_ENDIAN ])

Returns the positive integer represented by the eight bytes starting at the specified byteOffset in this object, in unsigned binary form.

The return value will be between 0 and 264 - 1, inclusive.

Throws RangeError if byteOffset is negative, or byteOffset + 8 is greater than the length of this object.

Source

int getUint64(int byteOffset, [Endianness endian = Endianness.BIG_ENDIAN]);