generate http.Transports for the clients.
  
  - `rest_client_transport_cache_entries` is a gauge metric
  with the number of existing entries in the internal cache
  
  - `rest_client_transport_create_calls_total` is a counter
  that increments each time a new transport is created, storing
  the result of the operation needed to generate it: hit, miss

  // iqn is Target iSCSI Qualified Name.
  optional string iqn = 2;

  // lun is iSCSI Target Lun number.
  optional int32 lun = 3;

  // iscsiInterface is the interface Name that uses an iSCSI transport.
  // Defaults to 'default' (tcp).
  // +optional
  optional string iscsiInterface = 4;

  // fsType is the filesystem type of the volume that you want to mount.