fix: stabilize mobile uploads and show transfer speed

packages/core/src/item.ts

@@ -134,7 +134,22 @@ async function* chunksOf(source: ContentSource): AsyncGenerator<Uint8Array, void
     return;
   }
   if (typeof Blob !== 'undefined' && source instanceof Blob) {
-    yield* chunksOf(source.stream());
+    if (typeof source.stream === 'function') {
+      yield* chunksOf(source.stream());
+      return;
+    }
+
+    // Older Safari releases don't expose Blob.stream(). Read bounded slices
+    // instead of materializing the complete file in memory.
+    const sliceSize = 256 * 1024;
+    for (let offset = 0; offset < source.size; offset += sliceSize) {
+      const part = source.slice(offset, Math.min(offset + sliceSize, source.size));
+      if (typeof part.arrayBuffer === 'function') {
+        yield new Uint8Array(await part.arrayBuffer());
+      } else {
+        yield await readBlobPart(part);
+      }
+    }
     return;
   }
   if (typeof ReadableStream !== 'undefined' && source instanceof ReadableStream) {
@@ -153,6 +168,18 @@ async function* chunksOf(source: ContentSource): AsyncGenerator<Uint8Array, void
   yield* source as AsyncIterable<Uint8Array>;
 }
 
+function readBlobPart(blob: Blob): Promise<Uint8Array> {
+  return new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onload = () => reader.result instanceof ArrayBuffer
+      ? resolve(new Uint8Array(reader.result))
+      : reject(new TypeError('文件读取失败'));
+    reader.onerror = () => reject(reader.error ?? new TypeError('文件读取失败'));
+    reader.onabort = () => reject(new DOMException('文件读取已取消', 'AbortError'));
+    reader.readAsArrayBuffer(blob);
+  });
+}
+
 interface Chunk {
   data: Bytes;
   last: boolean;