presto-memory/src/main/java/io/prestosql/plugin/memory/MemoryDataFragment.java/MemoryDataFragment/MemoryDataFragment
class MemoryDataFragment:    @JsonCreator
    public MemoryDataFragment(
            @JsonProperty("hostAddress") HostAddress hostAddress,
            @JsonProperty("rows") long rows)
    {
        this.hostAddress = requireNonNull(hostAddress, "hostAddress is null");
        checkArgument(rows >= 0, "Rows number can not be negative");
        this.rows = rows;
    }