Typed SegmentResponse model.
@type t() :: %ApolloSignal.Types.SegmentResponse{ contact_count: integer() | nil, created_at: String.t(), id: String.t(), name: String.t(), object: String.t() | nil, project_id: String.t(), unsubscribed_count: integer() | nil }
@spec from_map(map()) :: t()
@spec to_map(t()) :: map()