listen method
Listen for changes on the given connection.
Implementation
listen(JsRef conn, String key, void Function(dynamic) callback) {
context.runtime.onMessage(key, (json) => callback(TxReport.fromJson(json)));
var code = """
vendor.ds.listen(${conn.toJsCode()}, '$key', (report) => {
sendMessage('$key', JSON.stringify(report));
});
""";
return context.evaluate(code);
}