import std.algorithm, std.container, std.stdio;

​

struct DataPoint {

    immutable ulong time;

    ulong value;

}

​

void main() {

    auto dataPoints = DList!DataPoint([

        DataPoint(10, 1),

        DataPoint(30, 3),

        DataPoint(40, 4),

    ]);

    auto time = 30;

    auto r2 = until!(dp => dp.time >= time)(dataPoints[]);

    auto dp = dataPoints[].find(r2.front); // dp is DList!(...).Range so is usable in insertAfter

    writeln("before: ", dataPoints[]);

    dataPoints.insertAfter(dp, DataPoint(20, 2));

    writeln("after: ", dataPoints[]);

}

​