title: Dropbox upload stops when you leave uiviewcontrolelr
body: <p>i am facing issue in dropbox upload.</p>
  
  <p>When i am staying on the view on which i have written dropbox upload code then it works fine. But if in between upload process i leave the view and open another screen then upload stops or canceled.</p>
  
  <p>I am using below code</p>
  
  <pre><code>- (void)didPressLink {
      self.restClient = [[DBRestClient alloc] initWithSession:[DBSession sharedSession]];
      self.restClient.delegate = self;
      if(![[DBSession sharedSession] isLinked]) {
          [[DBSession sharedSession] linkFromController:self];
      }
  }
  
  -(void)saveFileOnDropBox{
      [self didPressLink];
      NSString *filename = [soundOneNew lastPathComponent];
      NSString *destDir = @"/";
      [[self restClient] uploadFile:filename toPath:destDir    withParentRev:nil fromPath:soundOneNew];
  }
  
  -(void)restClient:(DBRestClient*)client uploadedFile:(NSString*)destPath
           from:(NSString*)srcPath metadata:(DBMetadata*)metadata {
  
       NSLog(@"File uploaded successfully to path: %@ %@", metadata.path, destPath);
  
       [[self restClient] loadSharableLinkForFile: [NSString stringWithFormat:@"/%@",metadata.path]];
  }
  
  - (void)restClient:(DBRestClient*)client uploadFileFailedWithError:(NSError*)error {
      NSLog(@"File upload failed with error - %@", error);
  }
  
   - (void)restClient:(DBRestClient*)restClient loadedSharableLink:(NSString*)link
         forFile:(NSString*)path
  {
     NSLog(@"Sharable link %@",link);
     NSLog(@"File Path %@ ",path);
  
  }
  
  
  -(void) restClient:(DBRestClient *)client uploadProgress:(CGFloat)progress forFile:(NSString *)destPath from:(NSString *)srcPath {
     static NSDate* date = nil;
     static double oldUploadedFileSize = 0;
     if (!date) {
         date = [NSDate date] ;
     } else {
          NSTimeInterval sec = -[date timeIntervalSinceNow];
          date = [NSDate date] ;
         NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:srcPath error:nil];
         double uploadedFileSize = (double)[fileAttributes fileSize] * progress;
         if (sec) {
             NSLog(@"speed approx. %.2f KB/s", (uploadedFileSize - oldUploadedFileSize )/1024.0 / sec );
         }
         oldUploadedFileSize = uploadedFileSize;
         self.uploadAudioProgress.progress = progress;
      }
  }
  </code></pre>
  
  <p>How to keep upload process continue even if i leave the view</p>