title: AFAmazonS3Client how to define meta-data?
body: <p>Hi im using AFAmazonS3Client and im sending .mp3 file to my aws server. But its Content-Type is not "audio/mpeg" how can i change this.</p>
  
  <pre><code>AFAmazonS3Manager *s3Manager = [[AFAmazonS3Manager alloc] initWithAccessKeyID:@"..." secret:@"..."];
  s3Manager.region = AFAmazonS3USWest1Region;
  s3Manager.bucket = @"my-bucket-name";
  
  [s3Manager postObjectWithFile:mp3FilePath
            destinationPath:@"/"
                 parameters:nil
                   progress:^(NSUInteger bytesWritten, long long totalBytesWritten, long     long totalBytesExpectedToWrite) {
                      NSLog(@"%f%% Uploaded", (totalBytesWritten / (totalBytesExpectedToWrite * 1.0f) * 100)); }success:^(id responseObject) {
                      NSLog(@"Upload Complete"); } failure:^(NSError *error) { NSLog(@"Error: %@", error);}];
  </code></pre>