Most warnings fell into two categories:

 * Duplicated imports, either implicit from the prelude or specified
   multiple times.

 * Type parameter bounds specified in multiple places:

    warning: bound is defined in more than one place
       --> src/serialization/ser.rs:198:26
	|
    198 |     fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Error>
	|                          ^
    199 |     where
    200 |         T: serde::Serialize,
	|         ^

Each line is "key=value\n", including the final line:

    $ curl http://localhost:12345/connector/status
    status=OK
    serial=*
    version=3.0.2
    pid=54209
    address=localhost
    port=12345

This can be tested with the yubihsm-shell command:

    $ yubihsm-shell -a get-device-info
    Using default connector URL: http://127.0.0.1:12345
    Session keepalive set up to run every 15 seconds
    Version number:         2.2.0
    Serial number:          12345678
    Log used:               26/62
    Supported algorithms:   rsa-pkcs1-sha1, rsa-pkcs1-sha256, rsa-pkcs1-sha384,
			    rsa-pkcs1-sha512, rsa-pss-sha1, rsa-pss-sha256,
			    rsa-pss-sha384, rsa-pss-sha512, rsa2048,
			    rsa3072, rsa4096, ecp256,
			    ecp384, ecp521, eck256,
			    ecbp256, ecbp384, ecbp512,
			    hmac-sha1, hmac-sha256, hmac-sha384,
			    hmac-sha512, ecdsa-sha1, ecdh,
			    rsa-oaep-sha1, rsa-oaep-sha256, rsa-oaep-sha384,
			    rsa-oaep-sha512, aes128-ccm-wrap, opaque-data,
			    opaque-x509-certificate, mgf1-sha1, mgf1-sha256,
			    mgf1-sha384, mgf1-sha512, template-ssh,
			    aes128-yubico-otp, aes128-yubico-authentication, aes192-yubico-otp,
			    aes256-yubico-otp, aes192-ccm-wrap, aes256-ccm-wrap,
			    ecdsa-sha256, ecdsa-sha384, ecdsa-sha512,
			    ed25519, ecp224, rsa-pkcs1-decrypt,

This spins up a default MockHsm instance with the HTTP connector to
allow testing against external programs.