columns {
  name: "column0"
  type {
    type_id: UINT64
  }
}
columns {
  name: "column1"
  type {
    type_id: UINT64
  }
}
columns {
  name: "column2"
  type {
    type_id: UINT64
  }
}
columns {
  name: "key"
  type {
    type_id: UINT64
  }
}
rows {
  items {
    uint64_value: 26
  }
  items {
    uint64_value: 31
  }
  items {
    uint64_value: 5
  }
  items {
    uint64_value: 10
  }
}
rows {
  items {
    uint64_value: 48
  }
  items {
    uint64_value: 61
  }
  items {
    uint64_value: 6
  }
  items {
    uint64_value: 20
  }
}
