Type Alias sec_protocol_challenge_t 

pub type sec_protocol_challenge_t = *mut DynBlock<dyn Fn(sec_protocol_metadata_t, sec_protocol_challenge_complete_t)>;

Available on crate features SecProtocolMetadata and SecProtocolOptions and SecProtocolTypes and block2 only.

sec_protocol_challenge_t

Block to be invoked when the protocol instance is issued a challenge (e.g., a TLS certificate request).

Parameter metadata: A sec_protocol_metadata_t instance.

Parameter complete: A sec_protocol_challenge_complete_t to be invoked when the challenge is complete.

See also Apple’s documentation