feat: ensure large message batches can be received by subscribers (#1133

)

This is the earliest client version that will support larger message sizes when they are allowed.

google-cloud-pubsublite/src/main/java/com/google/cloud/pubsublite/internal/wire/ServiceClients.java

@@ -37,6 +37,10 @@ public final class ServiceClients {
   private static final int CLIENT_POOL_SIZE =
       Integer.parseInt(System.getProperty("PUBSUB_LITE_CHANNELS_PER_CLIENT", "10"));
 
+  // Set maximum inbound message size to 20 MiB to match Cloud Pub/Sub and ensure at least 1 10 MiB
+  // message can be received in a subscribe batch.
+  private static final int MAX_INBOUND_MESSAGE_SIZE = 20 * 1024 * 1024;
+
   private ServiceClients() {}
 
   private static TransportChannelProvider getTransportChannelProvider() {
@@ -47,6 +51,7 @@ private static TransportChannelProvider getTransportChannelProvider() {
         .setKeepAliveTimeout(Duration.ofMinutes(1))
         .setPoolSize(CLIENT_POOL_SIZE)
         .setExecutor(SystemExecutors.getFuturesExecutor())
+        .setMaxInboundMessageSize(MAX_INBOUND_MESSAGE_SIZE)
         .build();
   }