Dropping characters when USB Serial reads are slow

[obra]

We're trying to track down a USB Serial input issue with the GD32 Arduino core which is causing bytes to get dropped. It looks like the issue might be that the GD32 core's CDCACM implementation isn't using the same 64 byte ring buffer as other arduino cores seem to. (api/RingBuffer.h has typedef RingBufferN<SERIAL_BUFFER_SIZE> RingBuffer) - Not every core does appear to use it though.

This may be macOS specific.

To repro:

static constexpr char NEWLINE = '\n';
bool isEOL() {
  return Serial.peek() == NEWLINE;
}

void setup() {
  Serial.begin(9600);
  while (!Serial) { ; }
}

void loop() {
  uint16_t data[384] = {0 };
  int i = 0;
    while (! isEOL() && (i < 384))  {
      data[i]= Serial.parseInt();
      i++;
    } 

    Serial.println("Got data");
    for (auto j = 0; j<= sizeof(data); j++) { 
      Serial.print(data[j]);
      Serial.print(" ");
    }
    Serial.println("");
}

Pasting in

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Results in

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[bjc]

Closing this since the reported case is working. Remaining issues on #10 can be handled on that issue.