Fixed bug in the response header's parser

[SantyagoSeaman]

There was incorrect string slicing in case if header's value has symbol ":". For example header X-FB-Ads-Insights-Throttle: { "app_id_util_pct": 100, "acc_id_util_pct": 10 }

[ghost]

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[ghost]

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[brenjt]

Can we get this merged in. This is such a simple fix but not having such an important change is making managing the throttle near impossible without writing our own libraries.

[kickiss]

Hi guys! Will this fix ever be merged ?

[bartclaeys]

Seems like nobody follows this up?

[jimrubenstein]

FWIW there's a fix for this in master