** Use in 'AppModule' classes to denote a service builder method.
facet class Build {
    ** If not specified, the service id is taken to be the qualified name of the returned type. 
    ** Example:
    **   syntax: fantom
    **   @Build
    **   acme::MyService buildPenguin() { ... }
    ** defines a service with an id of 'acme::MyService'.
    const Str? serviceId    := null
    ** A list of scopes this service may be created in.
    const Str[]? scopes     := null

    ** A list of service ID aliases.
    const Str[]? aliases    := null

    ** A list of service Type aliases.
    const Type[]? aliasTypes:= null