change the type of the 1st para of Add from double[] to IEnumerable<double>

Author: shirok1

README.md

@@ -21,7 +21,7 @@ _"I'm sorry Dave... I'm afraid I can't do that"_
 * Source code for the WAV reading method is at the bottom of this page.
 
 ```cs
-(double[] audio, int sampleRate) = ReadWAV("hal.wav");
+(IEnumerable<double> audio, int sampleRate) = ReadWAV("hal.wav");
 var sg = new SpectrogramGenerator(sampleRate, fftSize: 4096, stepSize: 500, maxFreq: 3000);
 sg.Add(audio);
 sg.SaveImage("hal.png");
@@ -59,7 +59,7 @@ public Form1()
 
 Whenever an audio buffer gets filled, add the data to your Spectrogram:
 ```cs
-private void GotNewBuffer(double[] audio)
+private void GotNewBuffer(IEnumerable<double> audio)
 {
  sg.Add(audio);
 }
@@ -81,7 +81,7 @@ Review the source code of the demo application for additional details and consid
 This example demonstrates how to convert a MP3 file to a spectrogram image. A sample MP3 audio file in the [data folder](data) contains the audio track from Ken Barker's excellent piano performance of George Frideric Handel's Suite No. 5 in E major for harpsichord ([_The Harmonious Blacksmith_](https://en.wikipedia.org/wiki/The_Harmonious_Blacksmith)). This audio file is included [with permission](dev/Handel%20-%20Air%20and%20Variations.txt), and the [original video can be viewed on YouTube](https://www.youtube.com/watch?v=Mza-xqk770k).
 
 ```cs
-(double[] audio, int sampleRate) = ReadWAV("song.wav");
+(IEnumerable<double> audio, int sampleRate) = ReadWAV("song.wav");
 
 int fftSize = 16384;
 int targetWidthPx = 3000;
@@ -117,7 +117,7 @@ Spectrogram (2993, 817)
 These examples demonstrate the identical spectrogram analyzed with a variety of different colormaps. Spectrogram colormaps can be changed by calling the `SetColormap()` method:
 
 ```cs
-(double[] audio, int sampleRate) = ReadWAV("hal.wav");
+(IEnumerable<double> audio, int sampleRate) = ReadWAV("hal.wav");
 var sg = new SpectrogramGenerator(sampleRate, fftSize: 8192, stepSize: 200, maxFreq: 3000);
 sg.Add(audio);
 sg.SetColormap(Colormap.Jet);
@@ -141,7 +141,7 @@ Cropped Linear Scale (0-3kHz) | Mel Scale (0-22 kHz)
 Amplitude perception in humans, like frequency perception, is logarithmic. Therefore, Mel spectrograms typically display log-transformed spectral power and are presented using Decibel units.
 
 ```cs
-(double[] audio, int sampleRate) = ReadWAV("hal.wav");
+(IEnumerable<double> audio, int sampleRate) = ReadWAV("hal.wav");
 var sg = new SpectrogramGenerator(sampleRate, fftSize: 4096, stepSize: 500, maxFreq: 3000);
 sg.Add(audio);
 
@@ -166,7 +166,7 @@ SFF files be saved using `Complex` data format (with real and imaginary values f
 This example creates a spectrogram but saves it using the SFF file format instead of saving it as an image. The SFF file can then be read in any language.
 
 ```cs
-(double[] audio, int sampleRate) = ReadWAV("hal.wav");
+(IEnumerable<double> audio, int sampleRate) = ReadWAV("hal.wav");
 var sg = new SpectrogramGenerator(sampleRate, fftSize: 4096, stepSize: 700, maxFreq: 2000);
 sg.Add(audio);
 sg.SaveData("hal.sff");
@@ -210,7 +210,7 @@ plt.show()
 You should customize your file-reading method to suit your specific application. I frequently use the NAudio package to read data from WAV and MP3 files. This function reads audio data from a mono WAV file and will be used for the examples on this page.
 
 ```cs
-(double[] audio, int sampleRate) ReadWAV(string filePath, double multiplier = 16_000)
+(IEnumerable<double> audio, int sampleRate) ReadWAV(string filePath, double multiplier = 16_000)
 {
  using var afr = new NAudio.Wave.AudioFileReader(filePath);
  int sampleRate = afr.WaveFormat.SampleRate;
@@ -221,6 +221,6 @@ You should customize your file-reading method to suit your specific application.
  int samplesRead = 0;
  while ((samplesRead = afr.Read(buffer, 0, buffer.Length)) > 0)
  audio.AddRange(buffer.Take(samplesRead).Select(x => x * multiplier));
- return (audio.ToArray(), sampleRate);
+ return (audio, sampleRate);
 }
 ```

src/Spectrogram/SpectrogramGenerator.cs

@@ -82,7 +82,7 @@ public void AddCircular(float[] values) { }
  [Obsolete("use the Add() method", true)]
  public void AddScroll(float[] values) { }
 
- public void Add(double[] audio, bool process = true)
+ public void Add(IEnumerable<double> audio, bool process = true)
  {
  newAudio.AddRange(audio);
  if (process)