Add optional ReadData.prefetch(...) method

The default implementation does nothing

Author: tpietzsch

src/main/java/org/janelia/saalfeldlab/n5/readdata/ReadData.java

@@ -32,6 +32,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
+import java.util.Collection;
 import org.janelia.saalfeldlab.n5.N5Exception.N5IOException;
 import org.janelia.saalfeldlab.n5.codec.DataCodec;
 
@@ -222,6 +223,20 @@ default void writeTo(OutputStream outputStream) throws N5IOException, IllegalSta
 		}
 	}
 
+	/**
+	 * Indicates that the given slices will be subsequently read.
+	 * {@code ReadData} implementations (optionally) may take steps to prepare
+	 * for these subsequent slices.
+	 *
+	 * @param ranges
+	 * 		slice ranges to prefetch
+	 *
+	 * @throws N5IOException
+	 * 		if any I/O error occurs
+	 */
+	default void prefetch(final Collection<? extends Range> ranges) throws N5IOException {
+	}
+
 	// ------------- Encoding / Decoding ----------------
 	//