docs: function callNative (instanceId, tasks, callbackId) {
    let calls = []
    if (typeof tasks === 'string') {
      try {
        calls = JSON.parse(tasks)
      }
      catch (e) {
        console.error('invalid tasks:', tasks)
      }
    }
    else if (isArray(tasks)) {
      calls = tasks
    }
    const len = calls.length
    calls[len - 1].callbackId = (!callbackId && callbackId !== 0)
                                ? -1
                                : callbackId
    for (let i = 0; i < len; i++) {
      processCall(instanceId, calls[i])
    }
  }