Tangent revealed by [HER-1898] eritrix 3.1 misses many pages that Heritrix 3.0 catches

* Recorder
    use intended basis for GenericReplayCharSequence in-memory-prefix
* RecordingInputStream
    reveal internal ROS buffer size

commons/src/main/java/org/archive/io/RecordingInputStream.java

@@ -339,4 +339,13 @@ public class RecordingInputStream
     public void setLimits(long hardMax, long timeoutMs, long maxRateKBps) {
         recordingOutputStream.setLimits(hardMax, timeoutMs, maxRateKBps);
     }
+
+    /**
+     * Expose the amount of in-memory buffering used by the internal 
+     * recording stream. 
+     * @return int buffer size
+     */
+    public int getRecordedBufferLength() {
+        return recordingOutputStream.getBufferLength();
+    }
 }

commons/src/main/java/org/archive/util/Recorder.java

@@ -382,7 +382,7 @@ public class Recorder {
         InputStream ris = getContentReplayInputStream();
         ReplayCharSequence rcs =  new GenericReplayCharSequence(
                 ris,
-                this.ros.getBufferLength()/2, 
+                this.getRecordedInput().getRecordedBufferLength()/2, 
                 this.backingFileBasename + RECORDING_OUTPUT_STREAM_SUFFIX,
                 requestedCharset);
         ris.close();