@SuppressWarnings("unchecked")
  public static long estimateBase(Class cl, boolean debug) {
    return estimateBaseFromCoefficients(getSizeCoefficients(cl, debug), debug);
  }
Estimate the static space taken up by the fields of a class. This includes the space taken up
by by references (the pointer) but not by the referenced object. So the estimated size of an
array field does not depend on the size of the array. Similarly the size of an object
(reference) field does not depend on the object.
@param cl    class
@param debug debug flag
@return the size estimate in bytes.
hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java