@param write_op operation to add this action to
@param keys array of null-terminated char arrays representing keys to set
@param vals array of pointers to values to set
@param lens array of lengths corresponding to each value
@param num number of key/value pairs to set
Set key/value pairs on an object
@param write_op operation to add this action to @param keys array of null-terminated char arrays representing keys to set @param vals array of pointers to values to set @param lens array of lengths corresponding to each value @param num number of key/value pairs to set