fix

src/bgzf/mod.rs

@@ -257,7 +257,7 @@ impl std::io::Write for Writer {
             htslib::bgzf_write(
                 self.inner,
                 buf.as_ptr() as *mut libc::c_void,
-                buf.len() as u64,
+                buf.len(),
             )
         };
         if nbytes < 0 {