net/http: add http1 and http2 Server IdleTimeout

[bradfitz]

Add http.Server.IdleTimeout to limit the keep-alive idle time for http1 and http2 servers.

[gopherbot]

CL https://golang.org/cl/19159 mentions this issue.

[odeke-em]

If I may ask, this is going to entail us adding MaxIdleTimeout and MaxActiveTimeout to Server, right? And also we'll add defaults as you in have in CL 19159, true?
Or should we just expose a new function IdleTimeoutHook so that it takes these durations which if <= 0 means we should use the default durations?

[gopherbot]

CL https://golang.org/cl/21491 mentions this issue.

[bradfitz]

@odeke-em, the naming here is much easier if we don't consider HTTP/2 and PING frames as activity. Then we'd just call it IdleTimeout and be done with it.

But with HTTP/2, do we care about clients sending a PING or other useless frame every N seconds vs. actually sending real requests every N seconds? If so, we need names for both types of idle (network idle vs no-HTTP-requests idle). Or we define IdleTimeout to mean one thing, and give ReadTimeout the other meaning (see #16958 (comment))?

Opinions welcome. Ideally with sample documentation you'd tell users.

I got as far as:

        // ReadTimeout optionally specifies a maximum duration before                                                                                        
        // timing out reads of request headers. It does not include                                                                                          
        // request bodies. For requests after the first on a                                                                                                 
        // connection, this is timer starts upon receiving the first                                                                                         
        // byte. For keep-alive duration, see IdleTimeout.                                                                                                   
        ReadTimeout  time.Duration

        // IdleTime, is, uh....                                                                                                                              
        IdleTimeout time.Duration

/cc @rhysh @broady @adg @bmizerany

[bradfitz]

/cc @prabrisat1 too.