[SCB-85] simple metrics write file examples

[zhengyangyong]

Signed-off-by: zhengyangyong yangyong.zheng@huawei.com

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Simple write file samples and merge them

[coveralls]

Coverage decreased (-0.006%) to 87.462% when pulling fbe3a63 on zhengyangyong:SCB-85-2 into acf966a on apache:master.