# File lib/new_relic/agent/http_clients/curb_wrappers.rb, line 63
        def append_header_data( data )
          key, value = data.split( /:\s*/, 2 )
          @headers[ key.downcase ] = value
          @curlobj._nr_header_str ||= ''
          @curlobj._nr_header_str << data
        end