feat(browser): Limit transport buffer size (#18046)

We bumped this in
#11764 but this might
lead to too many concurrent connections in the long run.


closes #17592

Author: chargome

packages/browser/src/transports/fetch.ts

@@ -1,9 +1,11 @@
 import type { Transport, TransportMakeRequestResponse, TransportRequest } from '@sentry/core';
-import { createTransport } from '@sentry/core';
+import { createTransport, makePromiseBuffer } from '@sentry/core';
 import { clearCachedImplementation, getNativeImplementation } from '@sentry-internal/browser-utils';
 import type { WINDOW } from '../helpers';
 import type { BrowserTransportOptions } from './types';
 
+const DEFAULT_BROWSER_TRANSPORT_BUFFER_SIZE = 40;
+
 /**
  * Creates a Transport that uses the Fetch API to send events to Sentry.
  */
@@ -59,5 +61,9 @@ export function makeFetchTransport(
     }
   }
 
-  return createTransport(options, makeRequest);
+  return createTransport(
+    options,
+    makeRequest,
+    makePromiseBuffer(options.bufferSize || DEFAULT_BROWSER_TRANSPORT_BUFFER_SIZE),
+  );
 }