code: private void tailRecord(byte[] b, int off, int len) throws IOException {
          if(this.position >= this.buffer.length){
              this.ensureDiskStream().write(b, off, len);
              this.position += len;
          } else {
              assert this.buffer != null: "Buffer is null";
              int toCopy = (int)Math.min(this.buffer.length - this.position, len);
              assert b != null: "Passed buffer is null";
              System.arraycopy(b, off, this.buffer, (int)this.position, toCopy);
              this.position += toCopy;
              // TODO verify these are +1 -1 right
              if (toCopy < len) {
                  tailRecord(b, off + toCopy, len - toCopy);
              }
          }
      }
docs: Record without digesting.
  
  @param b Buffer to record.
  @param off Offset into buffer at which to start recording.
  @param len Length of buffer to record.
  
  @exception IOException Failed write to backing file.