docs: private SQLiteConnection tryAcquirePrimaryConnectionLocked(int connectionFlags) {
          // If the primary connection is available, acquire it now.
          SQLiteConnection connection = mAvailablePrimaryConnection;
          if (connection != null) {
              mAvailablePrimaryConnection = null;
              finishAcquireConnectionLocked(connection, connectionFlags); // might throw
              return connection;
          }
  
          // Make sure that the primary connection actually exists and has just been acquired.
          for (SQLiteConnection acquiredConnection : mAcquiredConnections.keySet()) {
              if (acquiredConnection.isPrimaryConnection()) {
                  return null;
              }
          }
  
          // Uhoh.  No primary connection!  Either this is the first time we asked
          // for it, or maybe it leaked?
          connection = openConnectionLocked(mConfiguration,
                  true /*primaryConnection*/); // might throw
          finishAcquireConnectionLocked(connection, connectionFlags); // might throw
          return connection;
      }