Replace microtime() usages with hrtime()

[Dzhuneyt]

Fixes #2214

There are 5 test failures, but they are not caused by this PR. They are failing on master as well.

[GrahamCampbell]

Would be better to declare a guzzle specific time function in https://github.com/guzzle/guzzle/blob/master/src/functions.php, instead of copy-pasting this code all over the place.

[Dzhuneyt]

Introduced a new wrapper function \GuzzleHttp\current_time().

[gmponos]

I am not sure why the discussion is resolved.. but unless if guzzle maintainers say otherwise I still insist on my proposal to mark the function current_time as internal and have it with underscore as _current_time... In the same way that it is done here, here and here... we can wait feedback from someone.

[gmponos]

The reason suggesting the underscore is only for consistency with the rest of them.. in general I am not in favor of it.. but none the less I believe that it should be marked as internal in order not to have it under BC promise.

[Llbe]

It must be 1e9 (nano) and not 1e7, please see https://3v4l.org/OidWu.

[Llbe]

I realized hrtime(true) will return a float on 32-bit systems. So it must be divided only if it's an int if I'm not mistaken? Or use hrtime(false) and handle the array.

I saw that the change to 1e7 pointed to https://3v4l.org/bZ1uo but I think the mistake is that hrtime isn't a UNIX timestamp, it's just a value. So they cannot be compared like that.

[Nyholm]

Thank you @Llbe. You are correct. One must never mix hrtime and microtime.

1e9 is correct. My bad.

[Dzhuneyt]

@Nyholm reverted back to 1e9. Let me know if further changes are needed or we can merge.

[Nyholm]

Thank you.

I see that you have not resolved @gmponos concern yet. If we mark the function as internal we can easily change it later if we want to. Say that we want to introduce superSpecificTime() that is available in PHP7.4. If we dont mark it as internal there is no BC way to introduce that. Also, it will be impossible to drop microtime().

[Dzhuneyt]

I see. Marked is as @internal now.

[Dzhuneyt]

@Nyholm is there something else that stops these changes from being "mergeable"?

[Nyholm]

Last thing then Im happy to merge.

[Nyholm]

One minor thing. All our other internal methods starts with an underscore. Please rename to _current_time()

[Dzhuneyt]

Renamed.

@Nyholm

[Nyholm]

Thank you

[GrahamCampbell]

Symfony has a polyfill for the hrtime function, actually. Maybe it would be better to use that.

[wirwolf]

Hello @Dzhuneyt, i create a fork of this repo and release this marge request into the new version(6.4.0).

Namespace compatibility is 100%, and you can use my changes if you patch composer.json in your projects

• replace "guzzlehttp/guzzle": "^6.3" to "someblackmagic/guzzle": "^6.4"
• add "guzzlehttp/guzzle": "6.3.*" into replace block

Fork link: https://github.com/SomeBlackMagic/guzzle/