fix: no crash when headers are already sent

[alexander-akait]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• documentation update
• typo fix
• metadata update

Motivation / Use-Case

fixes #1920

Breaking Changes

No

Additional Info

We don't generate 500 because you can use multiple dev middlewares

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.21%. Comparing base (0f9a6c9) to head (33811fe).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1929      +/-   ##
==========================================
+ Coverage   96.16%   96.21%   +0.04%     
==========================================
  Files          13       13              
  Lines         861      871      +10     
  Branches      248      252       +4     
==========================================
+ Hits          828      838      +10     
  Misses         33       33              

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