Tags a value as a variable.

variable should be used to initialize state in stateful functions. Typically, variable will be called with a value downstream of an initialization key. The init transformation will then pull all values tagged as variables in a function body and store them in a Module.

value JAX value to be tagged as variable.
name string name for the value.
key JAX value that is used to tie in value. Default value: None
mode string name for sow mode (see harvest documentation). Default value: 'strict'

The value that was passed in.