code: function cloneBuffer(buffer, offset = 0, length = buffer.length) {
      if (!context || context.isFake) {
          return buffer;
      }
      const numChannels = buffer.numberOfChannels;
      const cloned = context.createBuffer(numChannels, length, buffer.sampleRate);
      for (let i = 0; i < numChannels; i++) {
          cloned.getChannelData(i)
              .set(buffer.getChannelData(i).slice(offset, offset + length));
      }
      return cloned;
  }
docs: /*
  clone audio buffer