Determines the amount of RAM that may be used for buffering added documents before they are flushed as a new Segment. Generally for faster indexing performance it's best to flush by RAM usage instead of document count and use as large a RAM buffer as you can.
When this is set, the writer will flush whenever buffered documents use this much RAM. Pass in {@link #DISABLE_AUTO_FLUSH} to prevent triggering a flush due to RAM usage. Note that if flushing by document count is also enabled, then the flush will be triggered by whichever comes first.
The default value is {@link #DEFAULT_RAM_BUFFER_SIZE_MB}.
public virtual void SetRAMBufferSizeMB( doublemb );