await new BluebirdPromise((resolve, reject) => {
   const rd = createReadStream(path.join(appImagePath, arch === Arch.ia32 ? "32" : "64", "runtime"))
   rd.on("error", reject)
   const wr = createWriteStream(image)
   wr.on("error", reject)
   wr.on("finish", resolve)
   rd.pipe(wr)
 })

 return new Promise((resolve, reject) => {
   const reader = createReadStream(src)
   const writer = createWriteStream(dest, stats == null ? undefined : {mode: stats!!.mode})
   reader.on("error", reject)
   writer.on("error", reject)
   writer.on("open", () => {
     reader.pipe(writer)
   })
   writer.once("close", resolve)
 })

      const w = (index: number) => {
        if (index >= operations.length) {
          firstStream.end(this.fileMetadataBuffer)
          return
        }

        const operation = operations[index++]

        if (operation.kind === OperationKind.COPY) {
          const readStream = createReadStream(this.options.oldPackageFile, {
            fd: oldFileFd,
            autoClose: false,
            start: operation.start,
            // end is inclusive
            end: operation.end - 1,
          })
          readStream.on("error", reject)
          readStream.once("end", () => w(index))
          readStream.pipe(firstStream, {
            end: false
          })
        }
        else {
          // https://github.com/electron-userland/electron-builder/issues/1523#issuecomment-327084661
          // todo to reduce http requests we need to consolidate non sequential download operations (Multipart ranges)
          const requestOptions = this.createRequestOptions("get")
          requestOptions.headers!!.Range = `bytes=${operation.start}-${operation.end - 1}`
          const request = this.httpExecutor.doRequest(requestOptions, response => {
            // Electron net handles redirects automatically, our NodeJS test server doesn't use redirects - so, we don't check 3xx codes.
            if (response.statusCode >= 400) {
              reject(new HttpError(response))
            }

            response.pipe(firstStream, {
              end: false
            })
            response.once("end", () => w(index))
          })
          this.httpExecutor.addErrorAndTimeoutHandlers(request, reject)
          request.end()
        }
      }