resolve method
Resolves this image provider using the given context, returning a PdfImage The image is automatically added to the document
Implementation
PdfImage resolve(Context context, PdfPoint size, {double? dpi}) {
  final effectiveDpi = dpi ?? this.dpi;
  if (effectiveDpi == null || _cache[0] != null) {
    _cache[0] ??= buildImage(context);
    if (_cache[0]!.pdfDocument != context.document) {
      _cache[0] = buildImage(context);
    }
    return _cache[0]!;
  }
  final width = (size.x / PdfPageFormat.inch * effectiveDpi).toInt();
  final height = (size.y / PdfPageFormat.inch * effectiveDpi).toInt();
  if (!_cache.containsKey(width)) {
    _cache[width] ??= buildImage(context, width: width, height: height);
  }
  if (_cache[width]!.pdfDocument != context.document) {
    _cache[width] = buildImage(context, width: width, height: height);
  }
  return _cache[width]!;
}