Params

A union type: () | value | 2+ tuple. Represents the possible parameters of an endpoint's input/output: no parameters, a single parameter (a "stand-alone" value instead of a 1-tuple), and multiple parameters.

There are two views on parameters: ParamsAsAny, where the parameters are represented as instances of the union type, or ParamsAsVector, where the parameters are represented as a vector of size 0/1/2+.