$ SPX_ENABLED=1 composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
^C
*** SPX Report ***

Global stats:

  Called functions    :    27.5K
  Distinct functions  :      714

  Wall time           :    7.39s
  ZE memory           :   62.6MB

Flat profile:

 Wall time           | ZE memory           |
 Inc.     | *Exc.    | Inc.     | Exc.     | Called   | Function
----------+----------+----------+----------+----------+----------
  101.6ms |  101.6ms |   41.8MB |   41.8MB |       12 | Composer\Json\JsonFile::parseJson
   53.6ms |   53.6ms |     544B |     544B |        4 | Composer\Cache::sha256
    6.91s |   41.5ms |   41.5MB |   -7.5MB |        4 | Composer\Repository\ComposerRepository::fetchFile
    6.85s |   32.3ms |   47.5MB |    5.4MB |        5 | 1@Composer\Repository\ComposerRepository::loadProviderListings
    7.8ms |    7.8ms |       0B |       0B |        4 | Composer\Cache::write
    1.1ms |    1.1ms |     -72B |     -72B |        1 | Composer\Console\Application::Composer\Console\{closure}
  828.5us |  828.5us |     976B |     976B |       12 | Composer\Util\RemoteFilesystem::findHeaderValue
  497.6us |  49