Returns the value of the URI option if it is set and of the correct type (integer). Returns fallback if
the option is not set, set to an invalid type, or zero.
Zero is considered "unset", so URIs can be constructed like so, and still accept default values:
bson_strdup_printf ("mongodb://localhost/?connectTimeoutMS=%d", myvalue)
If myvalue is non-zero it is the connection timeout; if it is zero the driver uses the default timeout.
When reading an option that is an int64, this function will return the value as int32_t. If the value is
outside the range of a 32-bit integer, a warning will be emitted and fallback is returned instead.
SEEALSO:mongoc_uri_get_option_as_int64()