attentionMask property
Attention mask aligned 1:1 with ids (1 = real token, 0 = padding).
null when the tokenizer's convention has no notion of padding at this
stage (e.g. Gemma SentencePiece — a graph that pads echoes its own mask
in ForwardResult.attentionMask instead).
Implementation
final List<int>? attentionMask;