lib/aerospike/client.rb
def get_header(key, options = nil)
      policy = create_policy(options, Policy, default_read_policy)
      command = ReadHeaderCommand.new(@cluster, policy, key)
      execute_command(command)
      command.record
    end
def get_header(key, options = nil)
      policy = create_policy(options, Policy, default_read_policy)
      command = ReadHeaderCommand.new(@cluster, policy, key)
      execute_command(command)
      command.record
    end
Read record generation and expiration only for specified key.  Bins are not read.
  The policy can be used to specify timeouts.