code: func NewPool(initCap int) *Pool {
  	return &Pool{
  		initCap:         initCap,
  		varLenColPool:   &sync.Pool{New: func() interface{} { return newVarLenColumn(initCap, nil) }},
  		fixLenColPool4:  &sync.Pool{New: func() interface{} { return newFixedLenColumn(4, initCap) }},
  		fixLenColPool8:  &sync.Pool{New: func() interface{} { return newFixedLenColumn(8, initCap) }},
  		fixLenColPool16: &sync.Pool{New: func() interface{} { return newFixedLenColumn(16, initCap) }},
  		fixLenColPool40: &sync.Pool{New: func() interface{} { return newFixedLenColumn(40, initCap) }},
  	}
  }
docs: // NewPool creates a new Pool.