gistfile1.js

record Column {
    bytes name;
    bytes value;
    long timestamp;
    union { int, null } ttl;
}

// becomes...

record Column {
    bytes name;
    bytes value;
    Timestamp new_timestamp;
    Timestamp new_ttl;

    /* deprecated */
    long timestamp;
    union { int, null } ttl;
}

// post removal

record Column {
    bytes name;
    bytes value;
    Timestamp @aliases(["new_timestamp"]) timestamp;
    Timestamp @aliases(["new_ttl"]) ttl;
}