docs: protected InputStream readContent( BinaryKey key,
                                         Connection connection ) throws SQLException {
          try {
              // first search the contents which are in use
              InputStream is = readStreamFromStatement(USED_CONTENT_STMT_KEY, key, connection);
              if (is != null) {
                  // return the stream without closing the connection
                  return is;
              }
              // then search the contents which are in the trash
              is = readStreamFromStatement(UNUSED_CONTENT_STMT_KEY, key, connection);
              if (is != null) {
                  // return the stream without closing the connection
                  return is;
              }
              // we couldn't find anything, so close the connection
              tryToClose(connection);
              return null;
          } catch (Throwable t) {
              tryToClose(connection);
              throw t;
          }
      }