title: how could I check that whether a S3 bucket already exist in aws s3 with GO
body: <p>I am trying to find an efficient way to check whether a bucket exist in aws S3 service.
  I don't want to use the list bucket function of s3 go sdk 'listBuckets'
  I tried using 'headBucket' function but I think i am using it in the wrong way. any help would be appreciated!</p>