How to use the buffer.Buffer.allocUnsafe function in buffer

function buildConnReq() {
  const buf = Buffer.allocUnsafe(16);

  // connection id
  buf.writeUInt32BE(0x417, 0);
  buf.writeUInt32BE(0x27101980, 4);
  // action
  buf.writeUInt32BE(0, 8);
  // transaction id
  crypto.randomBytes(4).copy(buf, 12);

  return buf;
}

var out = buffer.slice(offset, offset + have);
      offset += have;
      if (!buffers)
        buffers = [out];
      else
        buffers.push(out);
      nread += out.byteLength;
    } else {
      assert(have === 0, 'have should not go down');
    }

    // Exhausted the output buffer, or used all the input create a new one.
    if (availOutAfter === 0 || offset >= chunkSize) {
      availOutBefore = chunkSize;
      offset = 0;
      buffer = Buffer.allocUnsafe(chunkSize);
    }

    if (availOutAfter === 0) {
      // Not actually done. Need to reprocess.
      // Also, update the availInBefore to the availInAfter value,
      // so that if we have to hit it a third (fourth, etc.) time,
      // it'll have the correct byte counts.
      inOff += inDelta;
      availInBefore = availInAfter;
    } else {
      break;
    }
  }

  self.bytesWritten = inputRead;
  _close(self);

var out = buffer.slice(offset, offset + have);
      offset += have;
      if (!buffers)
        buffers = [out];
      else
        buffers.push(out);
      nread += out.byteLength;
    } else if (have < 0) {
      assert(false, 'have should not go down');
    }

    // exhausted the output buffer, or used all the input create a new one.
    if (availOutAfter === 0 || offset >= chunkSize) {
      availOutBefore = chunkSize;
      offset = 0;
      buffer = Buffer.allocUnsafe(chunkSize);
    }

    if (availOutAfter === 0) {
      // Not actually done. Need to reprocess.
      // Also, update the availInBefore to the availInAfter value,
      // so that if we have to hit it a third (fourth, etc.) time,
      // it'll have the correct byte counts.
      inOff += inDelta;
      availInBefore = availInAfter;
    } else {
      break;
    }
  }

  self.bytesWritten = inputRead;
  _close(self);

// Special handle line number one. This is more efficient and simplifies the
    // rest of the algorithm. Read more than the regular column number in bytes
    // to prevent multiple reads in case multi byte characters are used.
    return findColumn(fd, column, '');
  }
  let lines = 0;
  // Prevent blocking the event loop by limiting the maximum amount of
  // data that may be read.
  let maxReads = 32; // bytesPerRead * maxReads = 512 kb
  const bytesPerRead = 16384;
  // Use a single buffer up front that is reused until the call site is found.
  let buffer = Buffer.allocUnsafe(bytesPerRead);
  while (maxReads-- !== 0) {
    // Only allocate a new buffer in case the needed line is found. All data
    // before that can be discarded.
    buffer = lines < line ? buffer : Buffer.allocUnsafe(bytesPerRead);
    bytesRead = readSync(fd, buffer, 0, bytesPerRead);
    // Read the buffer until the required code line is found.
    for (var i = 0; i < bytesRead; i++) {
      if (buffer[i] === 10 && ++lines === line) {
        // If the end of file is reached, directly parse the code and return.
        if (bytesRead < bytesPerRead) {
          return parseCode(buffer.toString('utf8', i + 1, bytesRead), column);
        }
        // Check if the read code is sufficient or read more until the whole
        // expression is read. Make sure multi byte characters are preserved
        // properly by using the decoder.
        const code = decoder.write(buffer.slice(i + 1, bytesRead));
        return findColumn(fd, column, code);
      }
    }
  }

function copyFromBuffer(n, list) {
  const ret = Buffer.allocUnsafe(n);
  var p = list.head;
  var c = 1;
  p.data.copy(ret);
  n -= p.data.length;
  while (p = p.next) {
    const buf = p.data;
    const nb = (n > buf.length ? buf.length : n);
    buf.copy(ret, ret.length - n, 0, nb);
    n -= nb;
    if (n === 0) {
      if (nb === buf.length) {
        ++c;
        if (p.next)
          list.head = p.next;
        else
          list.head = list.tail = null;

function allocNewPool(poolSize) {
  pool = Buffer.allocUnsafe(poolSize);
  pool.used = 0;
}

function tryCreateBuffer(size, fd, isUserFd) {
  var threw = true;
  var buffer;
  try {
    buffer = Buffer.allocUnsafe(size);
    threw = false;
  } finally {
    if (threw && !isUserFd) fs.closeSync(fd);
  }
  return buffer;
}

function allocNewPool(poolSize) {
  pool = Buffer.allocUnsafe(poolSize);
  pool.used = 0;
}

'use strict'

const Buffer = require('buffer').Buffer
const StringDecoder = require('string_decoder').StringDecoder
const decoder = new StringDecoder()
const errors = require('redis-errors')
const ReplyError = errors.ReplyError
const ParserError = errors.ParserError
var bufferPool = Buffer.allocUnsafe(32 * 1024)
var bufferOffset = 0
var interval = null
var counter = 0
var notDecreased = 0

/**
 * Used for integer numbers only
 * @param {JavascriptRedisParser} parser
 * @returns {undefined|number}
 */
function parseSimpleNumbers (parser) {
  const length = parser.buffer.length - 1
  var offset = parser.offset
  var number = 0
  var sign = 1