Best way to handle events that are too large for buffering

When looking through RawSocketSender to troubleshoot our other issue (see comment on #18), I noticed that RawSocketSender does not handle large events very well in send(). It assumes that flush() always makes enough capacity in the pendings buffer to save the new bytes. If the event was bigger than the buffer, you get a BufferOverflowException.

```
java.nio.BufferOverflowException
at java.nio.HeapByteBuffer.put(HeapByteBuffer.java:189)
at java.nio.ByteBuffer.put(ByteBuffer.java:859)
at org.fluentd.logger.sender.RawSocketSender.send(RawSocketSender.java:171)
```

Also, if every log message you send is larger than the buffer, then the RawSocketSender will attempt to flush to the socket on every message.

Is this the desired behavior? I could imagine adding a size check to the send() method that immediately returns false if the event is too large, to avoid the BufferOverflowException. Or perhaps the large event could skip the buffer and write directly out to the socket. Since we are already using a BufferedOutputStream, I also wonder why we need the internal pendings buffer at all?

What is the normal way of handling errors in RawSocketSender?

Beginne in RawSocketSender.send(), insbesondere beim pendings-Puffer und dem im Stacktrace gezeigten BufferOverflowException-Pfad; vergleiche dieses Verhalten mit der Verwendung von BufferedOutputStream. Ermittle und dokumentiere die vorgesehene Behandlung von Ereignissen, die größer als der Puffer sind, sowie von Senderfehlern, und überprüfe anschließend, dass das gewählte Verhalten durch Tests abgedeckt ist.

Vom Indexierungsmodell aus dem Issue-Text verfasst.