protected void advanceOffset(T len) {
		int sizeofLen = (int) arithmetic.sizeOf(len);
		offset =
			arithmetic.binaryOp(PcodeOp.INT_ADD, offsetBytes, offsetBytes, offset, sizeofLen, len);
	}
Advance the handle's offset (negative to rewind)

@param len the number of bytes to advance
Ghidra/Features/SystemEmulation/src/main/java/ghidra/pcode/emu/unix/DefaultEmuUnixFileHandle.java