BSON type for a 64-bit integer. This class cannot be instantiated and is only created during BSON decoding when a 64-bit integer cannot be represented as a PHP integer on a 32-bit platform. Versions of the driver before 1.5.0 would throw an exception when attempting to decode a 64-bit integer on a 32-bit platform.
During BSON encoding, objects of this class will convert back to a 64-bit integer type. This allows 64-bit integers to be roundtripped through a 32-bit PHP environment without any loss of precision. The __toString() method allows the 64-bit integer value to be accessed as a string.
注意: This class exists purely for 32-bit platforms. Applications on 64-bit platforms (i.e. PHP_INT_SIZE is 8) should never encounter this class during normal operation.