Can you provide an example of how to use PKCS#11 interface to connect MQTT on Android9.0?

[Runxing123]

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Platform/OS/Hardware/Device
Android9.0

Describe the question

public class TlsContextPkcs11Options extends CrtResource {
  Pkcs11Lib pkcs11Lib;
  String userPin;
  Long slotId;
  String tokenLabel;
  String privateKeyObjectLabel;
  String certificateFilePath;
  String certificateFileContents;

  public TlsContextPkcs11Options(Pkcs11Lib pkcs11Lib) {
    this.addReferenceTo(pkcs11Lib);
    this.pkcs11Lib = pkcs11Lib;
  }

  public TlsContextPkcs11Options withUserPin(String pin) {
    this.userPin = pin;
    return this;
  }

  public TlsContextPkcs11Options withSlotId(long slotId) {
    this.slotId = slotId;
    return this;
  }

  public TlsContextPkcs11Options withTokenLabel(String label) {
    this.tokenLabel = label;
    return this;
  }

  public TlsContextPkcs11Options withPrivateKeyObjectLabel(String label) {
    this.privateKeyObjectLabel = label;
    return this;
  }

  public TlsContextPkcs11Options withCertificateFilePath(String path) {
    this.certificateFilePath = path;
    return this;
  }

  public TlsContextPkcs11Options withCertificateFileContents(String contents) {
    this.certificateFileContents = contents;
    return this;
  }

  protected void releaseNativeHandle() {
  }

  protected boolean canReleaseReferencesImmediately() {
    return true;
  }
}

Which fields are definitely required in the TlsContextPkcs11Options instance? Can you help provide a sample code?

[TwistedTwigleg]

I believe the following settings are the minimal required settings for making an PKCS11 connection:

• pkcs11Lib
• userPin
• certificateFilePath

You can find sample code for creating an MQTT PKCS11 connection in the PKCS11 PubSub sample.
There is also a simplified PKCS11 connection sample here in this PR that might also be helpful as a reference as it only contains code for making a PKCS11 connection and nothing more: #233

Also: While we know the code compiles on Android, we have currently not run tests to ensure it works on Android at this time.