code: func (p *CONNECT) setVariableHeader() {
  	// Convert the Keep Alive to the slice.
  	keepAlive := encodeUint16(p.keepAlive)
  
  	// Create a variable header and set it to the Packet.
  	p.variableHeader = []byte{
  		0x00,             // Length MSB (0)
  		0x04,             // Length LSB (4)
  		0x4D,             // 'M'
  		0x51,             // 'Q'
  		0x54,             // 'T'
  		0x54,             // 'T'
  		0x04,             // Level(4)
  		p.connectFlags(), // Connect Flags
  		keepAlive[0],     // Keep Alive MSB
  		keepAlive[1],     // Keep Alive LSB
  	}
  }
docs: // setVariableHeader sets the variable header to the Packet.