docs: add stopCallback method example

[snitin315]

• This is a bugfix
• This is a feature
• This is a code refactor
• This is a test update
• This is a docs update
• This is a metadata update

For Bugs and Features; did you add new tests?

No

Motivation / Use-Case

add stopCallback method example.

Breaking Changes

None

Additional Info

No

[codecov]

Codecov Report

Merging #3876 (4863650) into master (4962424) will increase coverage by 1.64%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3876      +/-   ##
==========================================
+ Coverage   91.07%   92.72%   +1.64%     
==========================================
  Files          14       14              
  Lines        1334     1334              
  Branches      467      467              
==========================================
+ Hits         1215     1237      +22     
+ Misses        108       89      -19     
+ Partials       11        8       -3     

Impacted Files	Coverage Δ
lib/Server.js	93.64% <0.00%> (+2.11%)	⬆️

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