synchronized boolean refresh(DBRecord record) throws IOException {

		String f = record.getString(FileBytesAdapter.FILENAME_COL);
		long offset = record.getLongValue(FileBytesAdapter.OFFSET_COL);
		long sz = record.getLongValue(FileBytesAdapter.SIZE_COL);
		if (offset != fileOffset || sz != size || !StringUtils.equals(f, filename)) {
			return false;
		}

		BinaryField field = (BinaryField) record.getFieldValue(FileBytesAdapter.BUF_IDS_COL);

		int[] bufferIds = new BinaryCodedField(field).getIntArray();
		originalBuffers = new DBBuffer[bufferIds.length];
		for (int i = 0; i < bufferIds.length; i++) {
			originalBuffers[i] = adapter.getBuffer(bufferIds[i]);
		}

		field = (BinaryField) record.getFieldValue(FileBytesAdapter.LAYERED_BUF_IDS_COL);
		bufferIds = new BinaryCodedField(field).getIntArray();
		layeredBuffers = new DBBuffer[bufferIds.length];
		for (int i = 0; i < bufferIds.length; i++) {
			layeredBuffers[i] = adapter.getBuffer(bufferIds[i], originalBuffers[i]);
		}
		return true;
	}
FileBytes provides access to the all the byte values (both original and modified) from an
imported file.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/mem/FileBytes.java