Constant MAX_QUARTER_STREAM_ID 

pub const MAX_QUARTER_STREAM_ID: u64 = _; // 1_152_921_504_606_846_975u64

Largest legal Quarter Stream ID (RFC 9297 §2.1).

“The largest legal QUIC stream ID value is 2^62-1, so the largest legal value of the Quarter Stream ID field is 2^60-1.” A varint can carry more than that, so the excess has to be rejected here rather than assumed away.