DataBuffer getBuffer(DataBuffer buf, int id) throws IOException {
		if (recoveryFile == null) {
			throw new IOException("Version file is closed");
		}
		int vfIndex;
		try {
			vfIndex = bufferIndexMap.get(id);
		}
		catch (NoValueException e) {
			return null;
		}
		recoveryFile.get(buf, vfIndex);
		return buf;
	}
Get modified buffer associated with the specified storage index in the
original file.
@param buf data buffer
@param id buffer ID
@return data buffer or null if buffer has not been modified
@throws IOException if an IO error occurs
Ghidra/Framework/DB/src/main/java/db/buffers/RecoveryFile.java