@Override
  public String toString() {
    return "Region{" +
        "name='" + name + '\'' +
        ", type=" + type +
        ", keyConstraint='" + keyConstraint + '\'' +
        ", valueConstraint='" + valueConstraint + '\'' +
        ", diskStoreName='" + diskStoreName + '\'' +
        ", redundantCopies=" + redundantCopies +
        ", expirations=" + expirations +
        ", eviction=" + eviction +
        "} " + super.toString();
  }
this sets the memory size in megabytes and the eviction type to MEMORY_SIZE

@param memorySizeMb the memory size in megabytes
@throws IllegalArgumentException if type is already set to other values. This is to prevent
        users from trying to send conflicting json attributes
        such as {type:HEAP_PERCENTAGE,memorySizeMb:100}
geode-management/src/main/java/org/apache/geode/management/configuration/Region.java