@Override
		public InputBlockStream createInputBlockStream(LocalBufferFile bf) throws IOException {
			if (!bf.readOnly) {
				throw new IOException("Read stream only permitted on read-only buffer file");
			}
			return bf.new LocalFileInputBlockStream();
		}
A factory to supply the default implementation for create an {@link InputBlockStream}
Ghidra/Framework/DB/src/main/java/db/buffers/LocalBufferFile.java