feat(fomdata): added support for spec-compliant FormData & Blob types; (#5316)

lib/helpers/readBlob.js

@@ -0,0 +1,15 @@
+const {asyncIterator} = Symbol;
+
+const readBlob = async function* (blob) {
+  if (blob.stream) {
+    yield* blob.stream()
+  } else if (blob.arrayBuffer) {
+    yield await blob.arrayBuffer()
+  } else if (blob[asyncIterator]) {
+    yield* asyncIterator.call(blob);
+  } else {
+    yield blob;
+  }
+}
+
+export default readBlob;