code: public static synchronized Apptentive.DateTime getTimeAtInstall(Selector selector) {
  		ensureLoaded();
  		for (VersionHistoryEntry entry : versionHistoryEntries) {
  			switch (selector) {
  				case total:
  					// Since the list is ordered, this will be the first and oldest entry.
  					return new Apptentive.DateTime(entry.getTimestamp());
  				case version_code:
  					if (entry.getVersionCode() == RuntimeUtils.getAppVersionCode(ApptentiveInternal.getInstance().getApplicationContext())) {
  						return new Apptentive.DateTime(entry.getTimestamp());
  					}
  					break;
  				case version_name:
  					Apptentive.Version entryVersionName = new Apptentive.Version();
  					Apptentive.Version currentVersionName = new Apptentive.Version();
  					entryVersionName.setVersion(entry.getVersionName());
  					currentVersionName.setVersion(RuntimeUtils.getAppVersionName(ApptentiveInternal.getInstance().getApplicationContext()));
  					if (entryVersionName.equals(currentVersionName)) {
  						return new Apptentive.DateTime(entry.getTimestamp());
  					}
  					break;
  			}
  		}
  		return new Apptentive.DateTime(Util.currentTimeSeconds());
  	}
docs: Returns the number of seconds since the first time we saw this release of the app. Since the version entries are
  always stored in order, the first matching entry happened first.
  
  @param selector - The type of version entry we are looking for: total, version, or build.
  @return A DateTime representing the number of seconds since we first saw the desired app release entry. A DateTime with current time if never seen.