@Override
	public int read(byte[] b, int off, int len) throws IOException {
		for (int i = 0; i < len; i++) {
			int value = read();
			if (value < 0) {
				return i;
			}
			b[off + i] = (byte) value;
		}
		return len;
	}
ImageInputStream for reading images that wraps a MemBuffer to get the bytes.  Adds a method
to find out how many bytes were read by the imageReader to read the image.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/MemBufferImageInputStream.java