Definitions and functions used by the ADAS library to interface with viewer plugins.
Note: The file that defines adas_viewer_plugin_defs or adas_viewer_plugin_defs_[tag] (typically a .c or .cpp file) needs to define ADAS_VIEWER_PLUGIN_API_IMPLEMENT prior to including adas_viewer_plugin.h. Because other ADAS library header files could include adas_viewer_plugin.h, we recommend adding the #define ADAS_VIEWER_PLUGIN_API_IMPLEMENT prior to including any other ADAS library header file. If adas_viewer_plugin_defs_[tag] is used in multiple files, define this flag in only one of them.