Constant ECDSA_P521_SHA512_FIXED_SIGNING 

pub const ECDSA_P521_SHA512_FIXED_SIGNING: EcdsaSigningAlgorithm;

Available on crate features aws-lc and crypto and std only.

Signing of fixed-length (PKCS#11 style) ECDSA signatures using the P-521 curve and SHA-512.