Support stream output

[xepozz]

Implements https://github.com/yiisoft/yii-dev-panel/issues/13 Related https://github.com/yiisoft/yii-debug-api/pull/117

[what-the-diff[bot]]

PR Summary

• Changed while loop to do-while loop Improves code readability and flow.
• Added check for empty string before echoing output Prevents echoing empty outputs, enhancing efficiency.
• Flushes open buffers and sends echoed messages to the browser This prevents buffering issues when sending large responses, ensuring smoother performance with various server configurations.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.01 :tada:

Comparison is base (6094dba) 99.57% compared to head (23d89de) 99.58%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #50 +/- ## ============================================ + Coverage 99.57% 99.58% +0.01% - Complexity 75 77 +2 ============================================ Files 4 4 Lines 235 241 +6 ============================================ + Hits 234 240 +6 Misses 1 1 ``` | [Impacted Files](https://app.codecov.io/gh/yiisoft/yii-runner-http/pull/50?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yiisoft) | Coverage Δ | | |---|---|---| | [src/SapiEmitter.php](https://app.codecov.io/gh/yiisoft/yii-runner-http/pull/50?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yiisoft#diff-c3JjL1NhcGlFbWl0dGVyLnBocA==) | `100.00% <100.00%> (ø)` | |

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[samdark]

👍