/*
 * call-seq: to_json(state = nil, depth = 0)
 *
 * Returns a JSON string containing a JSON array, that is unparsed from
 * this Array instance.
 * _state_ is a JSON::State object, that can also be used to configure the
 * produced JSON string output further.
 * _depth_ is used to find out nesting depth, to indent accordingly.
 */
static VALUE mArray_to_json(int argc, VALUE *argv, VALUE self) {