TO_INTEGER

Converts an input value to an integer  value.The input can be a single- or multi-valued field or an expression. The input
type must be of a boolean, date, string or numeric type.Example:
```esql
ROW long = [5013792, 2147483647, 501379200000]
| EVAL int = TO_INTEGER(long)
```

Note that in this example, the last value of the multi-valued field cannot
be converted as an integer. When this happens, the result is a null value.
In this case a Warning header is added to the response. The header will
provide information on the source of the failure:"Line 1:61: evaluation of [TO_INTEGER(long)] failed, treating result as null. Only first 20 failures recorded."A following header will contain the failure reason and the offending value:"org.elasticsearch.xpack.ql.QlIllegalArgumentException: [501379200000] out of [integer] range"If the input parameter is of a date type, its value will be interpreted as
milliseconds since the Unix epoch,
converted to integer.Boolean true will be converted to integer 1, false to 0.Alias: TO_INT