bgzf/multithreaded_reader: Add virtual position getter

noodles-bgzf/src/multithreaded_reader.rs

@@ -7,7 +7,7 @@ use std::{
 
 use crossbeam_channel::{Receiver, Sender};
 
-use crate::Block;
+use crate::{Block, VirtualPosition};
 
 type BufferedTx = Sender<io::Result<Buffer>>;
 type BufferedRx = Receiver<io::Result<Buffer>>;
@@ -71,6 +71,11 @@ impl MultithreadedReader {
         self.position
     }
 
+    /// Returns the current virtual position of the stream.
+    pub fn virtual_position(&self) -> VirtualPosition {
+        self.buffer.block.virtual_position()
+    }
+
     /// Shuts down the reader and inflate workers.
     pub fn finish(&mut self) -> io::Result<()> {
         self.recycle_tx.take();