non_constant_identifier_names   
            
            Name non-constant identifiers using lowerCamelCase.
This rule is available as of Dart 2.0.0.
Rule sets: core, recommended, flutter
This rule has a quick fix available.
Details
DO name non-constant identifiers using lowerCamelCase.
Class members, top-level definitions, variables, parameters, named parameters and named constructors should capitalize the first letter of each word except the first word, and use no separators.
GOOD:
var item;
HttpRequest httpRequest;
align(clearItems) {
  // ...
}
Usage
To enable the non_constant_identifier_names rule,
add non_constant_identifier_names under linter > rules in your
analysis_options.yaml
file:
linter:
  rules:
    - non_constant_identifier_names