Rough example showing download bandwidth throttling with ASIHTTPRequest

gistfile1.m

- (void)handleBytesAvailable
{
	
	if (![self responseHeaders]) {
		if ([self readResponseHeadersReturningAuthenticationFailure]) {
			[self attemptToApplyCredentialsAndResume];
			return;
		}
	}
	if ([self needsRedirect]) {
		return;
	}
	
	int bufferSize = 2048;
	if (contentLength > 262144) {
		bufferSize = 65536;
	} else if (contentLength > 65536) {
		bufferSize = 16384;
	}
	
	if (!throttleMeasurementDate || [throttleMeasurementDate timeIntervalSinceNow] < -1.0) {
		[throttleMeasurementDate release];
		throttleMeasurementDate = [[NSDate date] retain];
		bytesReadSinceLastMeasurement = 0;
	}

	// Have we read more than 64KB in the last second?
	if (bytesReadSinceLastMeasurement + bufferSize > 65536) {
		bufferSize = 65536-bytesReadSinceLastMeasurement;
	}

	// Ensure we always read at least one byte or we'll stop receiving data
	if (bufferSize <= 0) {
		bufferSize = 1;
	}
	
    UInt8 buffer[bufferSize];
    CFIndex bytesRead = CFReadStreamRead(readStream, buffer, sizeof(buffer));
	
	
    // Less than zero is an error
    if (bytesRead < 0) {
        [self handleStreamError];
		
	// If zero bytes were read, wait for the EOF to come.
    } else if (bytesRead) {
		
		// Record how many bytes we've read for throttling
		bytesReadSinceLastMeasurement +=  bytesRead;
		
		[self setTotalBytesRead:[self totalBytesRead]+bytesRead];
		[self setLastActivityTime:[NSDate date]];
		//NSLog(@"%llu",[self totalBytesRead]);
		// Are we downloading to a file?
		if ([self downloadDestinationPath]) {
			if (![self fileDownloadOutputStream]) {
				BOOL append = NO;
				if (![self temporaryFileDownloadPath]) {
					[self setTemporaryFileDownloadPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[[NSProcessInfo processInfo] globallyUniqueString]]];
				} else if ([self allowResumeForFileDownloads]) {
					append = YES;
				}
				
				[self setFileDownloadOutputStream:[[[NSOutputStream alloc] initToFileAtPath:temporaryFileDownloadPath append:append] autorelease]];
				[fileDownloadOutputStream open];
			}
			[fileDownloadOutputStream write:buffer maxLength:bytesRead];
			
		//Otherwise, let's add the data to our in-memory store
		} else {
			[rawResponseData appendBytes:buffer length:bytesRead];
		}
    }
}