Experiment from entangled90

* single thread memory mapped file reader, pool of processors

* cleanup of inner classes of MetricProcessor

* doubles are parsed without external functions, strings are lazily created from byte arrays

* remove load() MappedByteBuffer in memory

* fixed handling of newline

* fix a bug & correct locale used

* MappedByteBuffer size set to 1MB

* fixed rounding

* Do not use ArrayBlockingQueue.offer since it drops elements when queue is full

* MappedByteBuffer size = 32 MB

calculate_average_entangled90.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+#  Copyright 2023 The original authors
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+
+JAVA_OPTS=""
+time java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_entangled90