code: public void setPreKeys(IdentityKey identityKey, SignedPreKeyRecord signedPreKey, List<PreKeyRecord> oneTimePreKeys)
        throws IOException
    {
      this.pushServiceSocket.registerPreKeys(identityKey, signedPreKey, oneTimePreKeys);
    }
docs: Register an identity key, signed prekey, and list of one time prekeys
  with the server.
  
  @param identityKey The client's long-term identity keypair.
  @param signedPreKey The client's signed prekey.
  @param oneTimePreKeys The client's list of one-time prekeys.
  
  @throws IOException