implements sending concurrent requests with curl multi

[lightbringer1991]

#hacktoberfest

This is an improvement as a partial answer to sendgrid/sendgrid-php#259

Allow requests to be sent concurrently.

Works exactly like the single request, but use curl_multi_ family.

[SendGridDX]

All committers have signed the CLA.

[thinkingserious]

This is awesome @lightbringer1991!

Could you please fix up the conflicts so we can merge? Thanks!

With Best Regards,

Elmer

[lightbringer1991]

hi, I have rebased with the latest master, could you please merge this PR, thank you.

[thinkingserious]

@caseyw, @vitya1, @Braunson, @cbschuld, @paoga87, @Taluu, @mazanax, @ninsuo, @ianh2, @WadeShuler, @jaimehing, @KnightAR

If you have a moment, I'd appreciate some extra eyes on this EPIC PR :)

[thinkingserious]

@lightbringer1991

We have not been able to merge your Pull Request, but because you are awesome - we wanted to make sure you could still get a SendGrid Hacktoberfest shirt.

Please go fill out our swag form before Nov 5th and we will send the shirt! (We know that you might have tried this before and it didn’t work, sorry about that!)

You have till Nov 5th to fill out this form in order to get the Hacktoberfest shirt!

Thank you for contributing during Hacktoberfest! We hope to see you in the repos soon! Just so you know, we always give away a SendGrid shirt for your first ever non-Hacktoberfest PR that gets merged.

[ninsuo]

whoops, I was notified by GitHub and thought you talked to me, I filled the form 😅
don't take it into account haha

[thinkingserious]

No worries @ninsuo :)

Thanks for the heads up!

[thinkingserious]

Hi @lightbringer1991,

Do you mind fixing these final conflicts so I can review and merge this in? Thank you!

With Best Regards,

Elmer

[codecov]

Codecov Report

Merging #24 into master will increase coverage by 12.24%.
The diff coverage is 79.16%.

@@             Coverage Diff             @@
##           master      #24       +/-   ##
===========================================
+ Coverage   70.43%   82.68%   +12.24%     
===========================================
  Files           3        3               
  Lines         115      179       +64     
===========================================
+ Hits           81      148       +67     
+ Misses         34       31        -3

Impacted Files	Coverage Δ
lib/Client.php	79.45% <79.16%> (+19.69%)	⬆️

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[lightbringer1991]

I have rebased with master, however, I cannot seem to fix all the code climate issues (toggle between complexity and multiple returns violation)
I'm not sure if the code complexity is so high that it is unmaintainable in this case, so maybe we can still merge it?

[thinkingserious]

Thank you @lightbringer1991!

I will review further and let you know my thoughts.

[thinkingserious]

Hello @lightbringer1991,

Thanks again for the PR!

We appreciate your contribution and look forward to continued collaboration. Thanks!

Team SendGrid DX