Couldnot get Time stamp for s3 files

[varunkubba]

I am using uber-s3 to fetch all the URLs that I have cahced in s3 Bucket. I also want the timestamps of the files at which they were cached, but I am not able to find any way to do this. Here is my code

require 'uber-s3'

s3=UberS3.new({
:access_key => Access_Key,
:secret_access_key => Secret_Access_key,
:bucket => Bucket_Name,
})
s3.objects('/').each do |obj|
puts obj.key
puts obj.last_modified
end