KAFKA-16770; [2/2] Coalesce records into bigger batches

clients/src/main/java/org/apache/kafka/common/record/MemoryRecordsBuilder.java

@@ -870,6 +870,14 @@ public boolean hasRoomFor(long timestamp, ByteBuffer key, ByteBuffer value, Head
         return this.writeLimit >= estimatedBytesWritten() + recordSize;
     }
 
+    /**
+     * Check if we have room for a given number of bytes.
+     */
+    public boolean hasRoomFor(int estimatedRecordsSize) {
+        if (isFull()) return false;
+        return this.writeLimit >= estimatedBytesWritten() + estimatedRecordsSize;
+    }
+
     public boolean isClosed() {
         return builtRecords != null;
     }