From c6ddbd55e2f30842499c200cffa309f7c78fa290 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 29 Mar 2019 19:57:52 +0100
Subject: [PATCH] Add a `progressiveDataLength` fast-path to
 `ChunkedStream.ensureByte`

This is *similar* to the existing check using in `ChunkedStream.ensureRange`.
---
 src/core/chunked_stream.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/core/chunked_stream.js b/src/core/chunked_stream.js
index 0be3140b0..26a93f673 100644
--- a/src/core/chunked_stream.js
+++ b/src/core/chunked_stream.js
@@ -98,6 +98,10 @@ class ChunkedStream {
   }
 
   ensureByte(pos) {
+    if (pos < this.progressiveDataLength) {
+      return;
+    }
+
     const chunk = Math.floor(pos / this.chunkSize);
     if (chunk === this.lastSuccessfulEnsureByteChunk) {
       return;