async runCallbacks () {
    try {
      await Promise.all(
        this.callbacks.map(([cb]) => {
          return cb()
        })
      )
    } catch (err) {
      this.callbacks.forEach(([, , reject]) => {
        reject()
      })
      throw err
    }
    this.callbacks.forEach(([, resolve]) => {
      resolve()
    })
    this.isReady = true
  }
Invokes the callbacks previous set by `svgthis.ready`
@function module:SVGthis.runCallbacks
@returns {Promise<void>} Resolves to `undefined` if all callbacks succeeded and rejects otherwise