curl --request POST \
  --url https://example.com/network/list \
  --header 'Content-Type: application/json' \
  --data '{
  "metadata": {}
}'

{
  "network_identifiers": [
    {
      "blockchain": "bitcoin",
      "network": "mainnet",
      "sub_network_identifier": {
        "network": "shard 1",
        "metadata": {
          "producer": "0x52bc44d5378309ee2abf1539bf71de1b7d7be3b5"
        }
      }
    }
  ]
}