private async Task ReadInternalAsync(Stream stream)
{
Signature = await GifHelpers.ReadStringAsync(stream, 3).ConfigureAwait(false);
if (Signature != "GIF")
{
throw GifHelpers.InvalidSignatureException(Signature);
}
Version = await GifHelpers.ReadStringAsync(stream, 3).ConfigureAwait(false);
if (Version != "87a" && Version != "89a")
{
throw GifHelpers.UnsupportedVersionException(Version);
}
LogicalScreenDescriptor = await GifLogicalScreenDescriptor.ReadAsync(stream).ConfigureAwait(false);
}