Fix wrong duration calculation for asynchronous calls

[oliverde8]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	fixes #X, partially #Y, mentioned in #Z
Documentation	if this is a new feature, link to pull request in https://github.com/php-http/documentation that adds relevant documentation
License	MIT

What's in this PR?

When using asnyc request, duration is always 0

This fixes that

Why?

Currenly for async request we don't see any duration.

First query is synchronous, the other 2 are asynchronous, and are slow. This fixes that

Now we can see the duration of asynchronous calls as well

Checklist

• Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
• Documentation pull request created (if not simply a bugfix)

[dbu]

thanks for the analysis! i think your solution is correct.

[joelwurtz]

Thanks for that, should be better yes

[dbu]

released as https://github.com/php-http/HttplugBundle/releases/tag/1.13.1