diff --git a/demos/browser/demo.js b/demos/browser/demo.js
index 36a2a75b..47fa2c2a 100644
--- a/demos/browser/demo.js
+++ b/demos/browser/demo.js
@@ -74,6 +74,7 @@ function startUpload() {
     chunkSize: chunkSize,
     retryDelays: [0, 1000, 3000, 5000],
     parallelUploads: parallelUploads,
+    uploadLengthDeferred: false,
     metadata: {
       filename: file.name,
       filetype: file.type
diff --git a/lib/browser/fileReader.js b/lib/browser/fileReader.js
index 14f6c4d1..72c7f36e 100644
--- a/lib/browser/fileReader.js
+++ b/lib/browser/fileReader.js
@@ -19,7 +19,8 @@ class FileSource {
     }
 
     const value = this._file.slice(start, end);
-    return Promise.resolve({ value });
+    const done = end >= this.size;
+    return Promise.resolve({ value, done });
   }
 
   close() {
diff --git a/lib/node/fileReader.js b/lib/node/fileReader.js
index 8d4a971d..69892f20 100644
--- a/lib/node/fileReader.js
+++ b/lib/node/fileReader.js
@@ -8,9 +8,10 @@ class BufferSource {
   }
 
   slice(start, end) {
-    let value = this._buffer.slice(start, end);
+    const value = this._buffer.slice(start, end);
     value.size = value.length;
-    return Promise.resolve({ value });
+    const done = end >= this.size;
+    return Promise.resolve({ value, done });
   }
 
   close() {}
@@ -75,6 +76,7 @@ class StreamSource {
       let buf = this._buf.slice(bufStart, bufEnd);
       buf.size = buf.length;
 
+      // TODO: Do we need to add the dpme value here?
       return Promise.resolve({ value: buf });
     }