Function ockam_ffi::ockam_vault_hkdf_sha256

#[no_mangle]
pub extern "C" fn ockam_vault_hkdf_sha256(
    context: FfiVaultFatPointer,
    salt: u64,
    input_key_material: *const u64,
    derived_outputs_attributes: *const FfiSecretAttributes,
    derived_outputs_count: u8,
    derived_outputs: *mut u64
) -> FfiOckamError

Perform an HMAC-SHA256 based key derivation function on the supplied salt and input key material.