Email Parser vs Stalwart mail-parser

Email Parser has no write-up on Specifiction yet; its figures are above.

Stalwart mail-parser is a free, open-source Rust library for parsing email messages. It supports Internet Message Format RFC 5322, MIME RFC 2045–2049 and other internet messaging RFCs, while attempting to handle messages that depart moderately from those standards. Parsed output includes a MIME tree, text and HTML body lists, and attachments. If one alternative is missing, the library can convert HTML to plain text or plain text to HTML. SIMD kernels accelerate scanning on supported targets, while transfer decoding and charset conversion wait until content is read. Returned strings generally reference the original input message. WHATWG encoding labels are recognized, and the optional full_encoding feature adds legacy multibyte sets including Shift_JIS, Big5 and GB18030. Defaults allow nesting depth 64, 10,000 MIME parts and three decoded nested-message levels. Rust 1.98 is required. No feature is enabled by default; serde adds serialization. The library is licensed under MIT or Apache-2.0 and costs nothing.