operator  method
The 32 or 64-bit two's complement integer at
address + (4 or 8) * index.
On 32-bit platforms this is a 32-bit integer, and on 64-bit platforms this is a 64-bit integer.
On 32-bit platforms a Dart integer is truncated to 32 bits (as if by
.toSigned(32)) before being stored, and the 32-bit value is
sign-extended when it is loaded.
On 32-bit platforms the
address must be 4-byte aligned, and on 64-bit
address must be 8-byte aligned.
external int operator (int index);