@Override
	int read(Buffer buf, int offset) throws IndexOutOfBoundsException, IOException {
		checkImmutable();
		int len = buf.getInt(offset);
		offset += 4;
		if (len < 0) {
			data = null;
		}
		else {
			data = buf.get(offset, len);
			offset += len;
		}
		return offset;
	}
Construct a binary data field with an initial value of data.
@param data initial value
@param immutable true if field value is immutable
Ghidra/Framework/DB/src/main/java/db/BinaryField.java