fix(bun): Consume fetch response body to prevent memory leak

Bun's fetch implementation retains the backing ArrayBuffer of unconsumed
response bodies indefinitely. This causes a memory leak when sending
many Sentry envelopes, as each response's ArrayBuffer accumulates in
memory.

This applies the same fix that was made for the Cloudflare transport in
getsentry#18545 — consuming the response body with response.text() after
extracting the needed headers.

In production, this leak manifests as ~8KB ArrayBuffers accumulating at
~8/sec (one per envelope), leading to OOM kills after ~5 hours on
containers with 4GB memory limits.

Author: Alp

packages/bun/src/transports/index.ts

@@ -14,7 +14,18 @@ export function makeFetchTransport(options: BaseTransportOptions): Transport {
 
     try {
       return suppressTracing(() => {
-        return fetch(options.url, requestOptions).then(response => {
+        return fetch(options.url, requestOptions).then(async response => {
+          // Consume the response body to prevent memory leaks in Bun's fetch implementation.
+          // Bun retains the backing ArrayBuffer of unconsumed response bodies indefinitely,
+          // causing memory to accumulate when sending many Sentry envelopes.
+          // See: https://github.com/getsentry/sentry-javascript/issues/18534
+          try {
+            await response.text();
+          } catch {
+            // We don't care about the response body, but consuming it is necessary
+            // to prevent memory leaks in Bun's fetch implementation
+          }
+
           return {
             statusCode: response.status,
             headers: {