Add FileBlob type

src/sdk/models/Data.ts

@@ -0,0 +1,15 @@
+export interface FileBlob {
+  type: string,
+  data: Uint8Array
+};
+
+export function isFileBlob(data: any): data is FileBlob {
+  return (
+    typeof data === 'object' &&
+    data !== null &&
+    'type' in data &&
+    typeof data.type === 'string' &&
+    'data' in data &&
+    data.data instanceof Uint8Array
+  );
+}