/// \brief Returns offset (since the beginning of the file, including
/// the File Preamble, if any) of the value of the current Dicom entry
/// \warning offset of the *value*, not of the Dicom entry
/// \brief Returns offset (since the beginning of the file, including
/// the File Preamble, if any) of the value of the current Dicom entry
/// \warning offset of the *value*, not of the Dicom entry