public void insertByte(int streampos, int val) {
		out[streampos] = (byte) val;
	}
Overwrite bytes that have already been written into the stream 
@param streampos is the index of the byte to overwrite
@param val is the value to overwrite with
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/PackedBytes.java