How to use the rsocket-core.UTF8Encoder.byteLength function in rsocket-core

export function encodeMetadata(
  service: string,
  method: string,
  tracing: Encodable,
  metadata: Encodable,
): Buffer {
  const serviceLength = UTF8Encoder.byteLength(service);
  const methodLength = UTF8Encoder.byteLength(method);
  const metadataLength = BufferEncoder.byteLength(metadata);
  // We can't overload the method call directly and the code generator currently only populates
  // the first 3 parameters
  if (undefined === tracing) {
    tracing = createBuffer(0);
  }
  const tracingLength = BufferEncoder.byteLength(tracing);

  const buffer = createBuffer(
    VERSION_SIZE +
      SERVICE_LENGTH_SIZE +
      serviceLength +
      METHOD_LENGTH_SIZE +
      methodLength +
      TRACING_LENGTH_SIZE +

export function encodeMetadata(
  service: string,
  method: string,
  tracing: Encodable,
  metadata: Encodable,
): Buffer {
  const serviceLength = UTF8Encoder.byteLength(service);
  const methodLength = UTF8Encoder.byteLength(method);
  const metadataLength = BufferEncoder.byteLength(metadata);
  // We can't overload the method call directly and the code generator currently only populates
  // the first 3 parameters
  if (undefined === tracing) {
    tracing = createBuffer(0);
  }
  const tracingLength = BufferEncoder.byteLength(tracing);

  const buffer = createBuffer(
    VERSION_SIZE +
      SERVICE_LENGTH_SIZE +
      serviceLength +
      METHOD_LENGTH_SIZE +
      methodLength +
      TRACING_LENGTH_SIZE +
      tracingLength +

(aggregate, key) => {
      const val = map[key];
      const keyLen = UTF8Encoder.byteLength(key);
      const keyBuf = createBuffer(keyLen);
      UTF8Encoder.encode(key, keyBuf, 0, keyLen);

      const valLen = UTF8Encoder.byteLength(val);
      const valBuf = createBuffer(valLen);
      UTF8Encoder.encode(val, valBuf, 0, valLen);

      const newEntries = aggregate.entries;
      newEntries.push({keyLen, keyBuf, valLen, valBuf});

      return {
        //4 for the sizes plus the actual key and actual value
        totalSize: aggregate.totalSize + 4 + keyLen + valLen,
        entries: newEntries,
      };
    },

(aggregate, key) => {
      const val = map[key];
      const keyLen = UTF8Encoder.byteLength(key);
      const keyBuf = createBuffer(keyLen);
      UTF8Encoder.encode(key, keyBuf, 0, keyLen);

      const valLen = UTF8Encoder.byteLength(val);
      const valBuf = createBuffer(valLen);
      UTF8Encoder.encode(val, valBuf, 0, valLen);

      const newEntries = aggregate.entries;
      newEntries.push({keyLen, keyBuf, valLen, valBuf});

      return {
        //4 for the sizes plus the actual key and actual value
        totalSize: aggregate.totalSize + 4 + keyLen + valLen,
        entries: newEntries,
      };
    },
    {totalSize: 0, entries: []},