SDK-normalized discriminant describing which StudioAiChatEvent fields
are populated. The transport derives it from the snake_case SSE event: line
using SSE_EVENT_NAME_TO_TYPE. The raw server JSON body's type retains
its PascalCase enum spelling; this union describes parsed SDK events.
SDK-normalized discriminant describing which StudioAiChatEvent fields are populated. The transport derives it from the snake_case SSE
event:line using SSE_EVENT_NAME_TO_TYPE. The raw server JSON body'styperetains its PascalCase enum spelling; this union describes parsed SDK events.