Check out example codes for "unable to update dart sdk. retrying". It will help you in understanding the concepts better.

Code Example 1

Add below path to Environment variable

User Variables

C:\flutter\bin; C:\Windows\System32

%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\

System Variables

C:\flutter\bin

C:\Windows\System32\

Code Example 2

restart your pc and delete flutter folder in C directroy then reinistall flutter and run flutter doctor

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