Cancel download throw error bugfix (Android)

Author: CapitanRedBeard

index.js

@@ -229,8 +229,14 @@ function fetch(...args:any):Promise {
     return fetchFile(options, method, url, headers, body)
   }
 
+  let promiseResolve;
+  let promiseReject;
+
   // from remote HTTP(S)
   let promise = new Promise((resolve, reject) => {
+    promiseResolve = resolve;
+    promiseReject = reject;
+
     let nativeMethodName = Array.isArray(body) ? 'fetchBlobForm' : 'fetchBlob'
 
     // on progress event listener
@@ -371,6 +377,7 @@ function fetch(...args:any):Promise {
     subscriptionUpload.remove()
     stateEvent.remove()
     RNFetchBlob.cancelRequest(taskId, fn)
+    promiseReject(new Error("canceled"))
   }
   promise.taskId = taskId