D言語でVST/AUプラグイン開発2 (エフェクト自作) ref: https://qiita.com/ShigekiKarita/items/9b3aa8f716848278ef62

file0.d

    override void reset(double sampleRate, int maxFrames, int numInputs, int numOutputs) nothrow @nogc
    {
        // DAW側でsampleRateが変更されたときに呼ばれる?
        if (this._sampleRate != sampleRate)
        {
            // 処理用のsampleRateを変更
            this._sampleRate = sampleRate;
            // RingBufferのサイズも変更
            this._buffer[0] = RingBuffer!float(this.maxDelayTimeFrame);
            this._buffer[1] = RingBuffer!float(this.maxDelayTimeFrame);
            // 新しいsampleRateにおけるUI上のdelayTimeをRingBufferに反映
            this.resetInterval();
        }
    }

file1.d

module ringbuffer;

struct RingBuffer(T)
{
     ...
}

unittest
{
    auto buf = RingBuffer!float(3);
    assert(buf[] == [0.0, 0.0, 0.0]);
    buf.setInterval(2);
    assert(buf.readIndex == 0);
    assert(buf.writeIndex == 2);
    assert(buf.front == 0);
    buf.pushBack(1.0);
    buf.pushBack(2.0);
    buf.pushBack(3.0);
    assert(buf[] == [2.0, 3.0, 1.0]);
}

file2.d

module main;
import dplug.core, dplug.client, dplug.vst;

version (unittest)
{}
else
{
    // This create the DLL entry point
    mixin(DLLEntryPoint!());
    // This create the VST entry point
    mixin(VSTEntryPoint!SimpleDelay);
}

file3.d

// 悪い例, 左右がズレて聞こえる
override void processAudio(const(float*)[] inputs, float*[]outputs, int frames, TimeInfo info) nothrow @nogc
{
    foreach (ch; 0..2)
        foreach (t; 0 .. frames)
            ...     

file4.d

// 良い例，左右のズレはなさそう
override void processAudio(const(float*)[] inputs, float*[]outputs, int frames, TimeInfo info) nothrow @nogc
{
    foreach (t; 0 .. frames)
        foreach (ch; 0..2)
            ...