Tests the production speed for a specified byte count.
Original signature is '- (float) testProductionSpeedForLength:(uint32_t)length'


- length (UInt32)
- The length of the test in bytes.

The maximum speed data can be produced at.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)