HttpServer Keep-Alive

[ENMOJY]

When I try to use http long connection, I set the timeout and maximum number to 10, the response received by my browser is still "Connection:close"

After I set the breakpoint, I found that "req.get_header_value("Connection") == "close"" is FALSE, but the return value of "req.get_header_value("Connection")" is " ". Why does "==" behave like this?