# File lib/docker/image.rb, line 267
    def build_from_tar(tar, opts = {}, connection = Docker.connection,
                       creds = nil, &block)

      headers = build_headers(creds)

      # The response_block passed to Excon will build up this body variable.
      body = ""
      connection.post(
        '/build', opts,
        :headers => headers,
        :response_block => response_block(body, &block)
      ) { tar.read(Excon.defaults[:chunk_size]).to_s }

      new(connection,
          'id' => Docker::Util.extract_id(body),
          :headers => headers)
    end