OptionalmaintainOptionalunderscoreIf true, an underscore is added before each digit when converting
camelCase to snake_case. For example foo12Bar => foo_12_bar and
foo_12_bar => foo12Bar
Defaults to false.
OptionalunderscoreIf true, an underscore is added between consecutive upper case
letters when converting from camelCase to snake_case. For example
fooBAR => foo_b_a_r and foo_b_a_r => fooBAR.
Defaults to false.
OptionalupperIf true, camelCase is transformed into upper case SNAKE_CASE.
For example fooBar => FOO_BAR and FOO_BAR => fooBar
Defaults to false.
If true, nested object's keys will not be converted to camel case.
Defaults to false.