Session initialization event.
@type t() :: %GeminiCliSdk.Types.InitEvent{ extra: map(), model: String.t(), session_id: String.t(), timestamp: String.t() | nil, type: String.t() }
@spec from_map(map()) :: t()
@spec parse(map() | t()) :: {:ok, t()} | {:error, {:invalid_init_event, CliSubprocessCore.Schema.error_detail()}}
@spec parse!(map() | t()) :: t()
@spec schema() :: Zoi.schema()
@spec to_map(t()) :: map()