Curious why SignalPreKeyMessage appears to be unsupported

[Manbearpixel]

I've noticed in the codebase that most references to SignalPreKeyMessage have been commented out and thus unsupported for use.

Was there a specific reason or decision that led to this? In the JAVA library this appears to be used and is working.

One example: Classes/SignalSessionBuilder.m

/*
- (void) processPreKeyMessage:(SignalPreKeyMessage*)preKeyMessage {
    NSParameterAssert(preKeyMessage);
    if (!preKeyMessage) { return; }
    session_record *record = NULL;
    //int result = session_record_create(&record, <#session_state *state#>, <#signal_context *global_context#>)
    //int result = session_builder_process_pre_key_signal_message(_builder, <#session_record *record#>, <#pre_key_signal_message *message#>, <#uint32_t *unsigned_pre_key_id#>)
}
 */

[Manbearpixel]

I'm trying to run through the test located in Testing/SignalProtocolTests/SignalProtocolObjCTests.m and am hitting Error Domain=org.whispersystems.SignalProtocol Code=4 "Invalid Key" UserInfo={NSLocalizedDescription=Invalid Key}

And am unsure how to resolve, or how the key could be invalid following the steps verbatim. Here I see a commented out reference to SignalPreKeyMessage but unsure if that was necessary there to have the test work properly.

Appreciate any guidance!