Constant DEFAULT_STREAM_CACHE_THRESHOLD 

pub const DEFAULT_STREAM_CACHE_THRESHOLD: usize = _; // 131_072usize

Default stream cache threshold (128 KB).

Streams exceeding this size will fail with CamelError::StreamLimitExceeded. This is intentionally conservative for OOM protection. For general-purpose materialization, use Body::materialize() (10 MB default).