Your data.
In order.

using ZoneTree;

using var tree = new ZoneTreeFactory<int, string>()
    .SetDataDirectory("data/my-tree")
    .OpenOrCreate();
using var maintainer = tree.CreateMaintainer();

tree.Upsert(42, "Hello, ZoneTree");

if (tree.TryGet(42, out var value))
    Console.WriteLine(value);

using ZoneTree;

using var tree = new ZoneTreeFactory<int, string>()
    .SetDataDirectory("data/my-tree")
    .OpenOrCreate();
using var maintainer = tree.CreateMaintainer();

using var iterator = tree.CreateIterator();
iterator.Seek(100);

while (iterator.Next() && iterator.CurrentKey < 200)
    Console.WriteLine($"{iterator.CurrentKey}: {iterator.CurrentValue}");