pub const MAX_CONCURRENCY: usize = 50;Expand description
Upper bound on MessagesApi::search_summaries’s concurrency
parameter, regardless of what the caller (CLI --concurrency or the MCP
concurrency param) requests.
Gmail’s quota is 250 units/user/second and messages.get costs 5 units,
so more than 50 requests in flight at once already assumes every one
completes within a second — the flag exists to bound the fan-out against
that quota, so it shouldn’t itself accept a value that can blow past it.