code: def set_basic_auth(client, secret)
        FHIR.logger.info 'Configuring the client to use HTTP Basic authentication.'
        token = Base64.encode64("#{client}:#{secret}")
        value = "Basic #{token}"
        @security_headers = { 'Authorization' => value }
        @use_oauth2_auth = false
        @use_basic_auth = true
        @client = RestClient
        @client.proxy = proxy unless proxy.nil?
        @client
      end
docs: Set the client to use HTTP Basic Authentication