class AwsService
  class ConfigurationError < StandardError
  end

  attr_reader bucket: String
  attr_reader s3_client: Aws::S3::Client

  def initialize: () -> void

  def upload_stream: (IO io, String key) -> Aws::S3::Types::PutObjectOutput

  def file_exists?: (String key) -> bool

  private

  def credentials: () -> Hash[Symbol, String]

  def validate_credentials!: () -> void
end