class Aws::DefaultsModeConfigResolver

def application_current_region
  resolved_region = @@application_region_mutex.synchronize do
    return @@application_region unless @@application_region.nil?
    region = nil
    if ENV['AWS_EXECUTION_ENV']
      region = ENV['AWS_REGION'] || ENV['AWS_DEFAULT_REGION']
    end
    if region.nil? && ENV['AWS_EC2_METADATA_DISABLED']&.downcase != "true"
      begin
        region = @@imds_client.get('/latest/meta-data/placement/region')
      rescue
        # unable to get region, leave it unset
      end
    end
    # required so that we cache the unknown/nil result
    @@application_region = region || :unknown
  end
  resolved_region == :unknown ? nil : resolved_region
end