Fix handling sync multiple control frames

[codecov[bot]]

Codecov Report

Patch coverage: 56.86% and project coverage change: +0.16 :tada:

Comparison is base (f55dac4) 48.69% compared to head (3f89ebd) 48.85%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #29 +/- ## ========================================== + Coverage 48.69% 48.85% +0.16% ========================================== Files 34 34 Lines 3401 3410 +9 ========================================== + Hits 1656 1666 +10 + Misses 1745 1744 -1 ``` | [Impacted Files](https://codecov.io/gh/ntex-rs/ntex-amqp/pull/29?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs) | Coverage Δ | | |---|---|---| | [src/session.rs](https://codecov.io/gh/ntex-rs/ntex-amqp/pull/29?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs#diff-c3JjL3Nlc3Npb24ucnM=) | `40.00% <38.88%> (+0.51%)` | :arrow_up: | | [src/sndlink.rs](https://codecov.io/gh/ntex-rs/ntex-amqp/pull/29?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs#diff-c3JjL3NuZGxpbmsucnM=) | `41.02% <50.00%> (-0.40%)` | :arrow_down: | | [src/dispatcher.rs](https://codecov.io/gh/ntex-rs/ntex-amqp/pull/29?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs#diff-c3JjL2Rpc3BhdGNoZXIucnM=) | `42.78% <73.91%> (+2.55%)` | :arrow_up: | ... and [1 file with indirect coverage changes](https://codecov.io/gh/ntex-rs/ntex-amqp/pull/29/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs) Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=ntex-rs)

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