ConvertErr2Status 内部转换，为了让err=nil的时候，监控数据里有OK信息.

Err2GrpcCode converts a standard Go error into its canonical code.

GrpcCodeToHTTP gRPC转HTTP Code.

IsRetryableHTTP returns if the provided error is considered retryable HTTP error.

IsRetryableNetwork returns if the provided error is a retryable network related error.

IsTemporary returns true if the provided error is considered retryable temporary error by testing if it complies with an interface implementing `Temporary() bool` and calling the function.

IsTemporaryConnection returns if the provided error was a low level retryable connection error.

IsTimeout returns true if the provided error is considered a retryable timeout error by testing if it complies with an interface implementing `Timeout() bool` and calling the function.

ParseError try to convert an error to *Error.