Where is a good place to call the VSTPluginFormat::dispatcher?

I am creating a vst3 plugin that acts a wrapper for a vst2 plugin. At some point I must call the VST2 dispatcher during runtime to gain some additonal info from the plugin.

VSTPluginFormat::dispatcher (AudioPluginInstance plugin, int32 opcode, int32 index, pointer_sized_int value, void* ptr, float opt)*

Where is a save place to call it to avoid race conditions?