A function to split a range into several ranges of different chunks

[Andrej Mitrovic]

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import std.range;
import std.stdio;

void main ()
{
     auto range = sequence!((a, n) => n);

     // works, but the chunks are all the same length
     auto rngs = range.chunks(4);
     writeln(rngs[0]);
     writeln(rngs[1]);
     writeln(rngs[2]);

     // want this
     auto ranges = range.???(3, 4, 5);
     writeln(ranges[0] == [1, 2, 3]);
     writeln(ranges[1] == [4, 5, 6, 7]);
     writeln(ranges[2] == [8, 9, 10, 11, 12]);
}
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Do you know of a simple way to do this? It's essentially similar 
to chunks, except the chunks themselves would not be of the same 
length.

You can think of a good name for '???' here. Maybe this is 
already possible by combining functionality in std.range - but I 
came up short.