Observable<DeviceCredential> getCredentials() {
    return deviceCredentialService()
            .getCredentials()
            .flatMapIterable(event -> event.getData());
  }

  Single<Organization> getOrgFromCreds(String orgid) {
    return getCredentials()
      .map(DeviceCredential::getOrganization)
      .filter(org -> org.getId().equals(orgid))
      .take(1)  // Without this I get an exception
      .singleOrError();
  }

  Function<Organization, Observable<Reader.EnrollmentState>> pairReader(String name) {
    return org -> readerService().pair(name, org);
  }

getOrgFromCreds(orgid)
  .flatMapObservable(pairReader(readerid))
  .subscribe(state -> {
     switch(state) {
       case BEGUN:
         LOG.d(TAG, "Pairing begun");
         break;
       case PAIRED:
         LOG.d(TAG, "Pairing success");
         callback.success();
         break;
       case NOTIFIED_SERVER:
         LOG.d(TAG, "Pairing server notified");
         break;
     }},
     error -> {
       Crashlytics.logException(error);
       callback.error(error.getLocalizedMessage());
     });

Single<Organization> getOrgFromCreds(String orgid) {
    return getCredentials()
      .map(DeviceCredential::getOrganization)
      .filter(org -> org.getId().equals(orgid))
      .firstOrError();
  }