+/* Creates and returns a new casewriter whose cases are passed
+ through TRANSLATE, which must create case OUTPUT, with
+ OUTPUT_VALUE_CNT values, and populate it based on INPUT and
+ auxiliary data AUX. The translated cases are then written to
+ SUBWRITER. TRANSLATE must also destroy INPUT.
+
+ When the translating casewriter is destroyed, DESTROY will be
+ called to allow any state maintained by TRANSLATE to be freed.
+
+ After this function is called, SUBWRITER must not ever again
+ be referenced directly. It will be destroyed automatically
+ when the translating casewriter is destroyed. */