int8: -128 ~ 127
int16: -32768 ~ 32767
int32: -2147483648 ~ 2147483647
int64: -9223372036854775808 ~ 9223372036854775807

uint8: 0 ~ 255
uint16: 0 ~ 65535
uint32: 0 ~ 4294967295
uint64: 0 ~ 18446744073709551615