throw new NullPointerException();
    }
    for (K k : keySet()) {
      checkValid(k);
    }
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return delegate.ceilingEntry(checkValid(key));
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return delegate.ceilingKey(checkValid(key));
  }

  @Override
  public void clear() {
    delegate.clear();
  }

    this.delegate = delegate;
    for (E e : this) {
      checkValid(e);
    }
  }

  @Override
  public boolean add(E element) {
    return delegate.add(checkValid(element));
  }

  @Override
  public boolean addAll(Collection<? extends E> collection) {
    for (E e : collection) {
      checkValid(e);
    }
    return delegate.addAll(collection);
  }

  @Override

      throw new NullPointerException();
    }
    for (K k : keySet()) {
      checkValid(k);
    }
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return delegate.ceilingEntry(checkValid(key));
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return delegate.ceilingKey(checkValid(key));
  }

  @Override
  public void clear() {
    delegate.clear();
  }

    this.delegate = delegate;
    for (E e : this) {
      checkValid(e);
    }
  }

  @Override
  public boolean add(E element) {
    return delegate.add(checkValid(element));
  }

  @Override
  public boolean addAll(Collection<? extends E> collection) {
    for (E e : collection) {
      checkValid(e);
    }
    return delegate.addAll(collection);
  }

  @Override

	if err := f.checkValid("SetReadDeadline"); err != nil {
		return err
	}
	return f.pfd.SetReadDeadline(t)
}

// setWriteDeadline sets the write deadline.
func (f *File) setWriteDeadline(t time.Time) error {
	if err := f.checkValid("SetWriteDeadline"); err != nil {
		return err
	}
	return f.pfd.SetWriteDeadline(t)
}

// checkValid checks whether f is valid for use.

type rawConn struct {
	file *File
}

func (c *rawConn) Control(f func(uintptr)) error {
	if err := c.file.checkValid("SyscallConn.Control"); err != nil {
		return err
	}
	err := c.file.pfd.RawControl(f)
	runtime.KeepAlive(c.file)
	return err
}

func (c *rawConn) Read(f func(uintptr) bool) error {
	if err := c.file.checkValid("SyscallConn.Read"); err != nil {
		return err
	}
	err := c.file.pfd.RawRead(f)

	zw := gzip.NewWriter(w)
	defer zw.Close()
	_, err := zw.Write(b)
	return err
}

// CheckValid tests whether the profile is valid. Checks include, but are
// not limited to:
//   - len(Profile.Sample[n].value) == len(Profile.value_unit)
//   - Sample.id has a corresponding Profile.Location
func (p *Profile) CheckValid() error {
	// Check that sample values are consistent
	sampleLen := len(p.SampleType)

func (f *File) setWriteDeadline(time.Time) error {
	if err := f.checkValid("SetWriteDeadline"); err != nil {
		return err
	}
	return poll.ErrNoDeadline
}

// checkValid checks whether f is valid for use, but does not prepare
// to actually use it. If f is not ready checkValid returns an appropriate
// error, perhaps incorporating the operation name op.
func (f *File) checkValid(op string) error {
	if f == nil {
		return ErrInvalid

// scan is passed in for use by checkValid to avoid an allocation.
// checkValid returns nil or a SyntaxError.
func checkValid(data []byte, scan *scanner) error {
	scan.reset()
	for _, c := range data {
		scan.bytes++
		if scan.step(scan, c) == scanError {
			return scan.err
		}
	}
	if scan.eof() == scanError {
		return scan.err
	}
	return nil
}

// It returns the number of bytes read and any error encountered.
// At end of file, Read returns 0, io.EOF.
func (f *File) Read(b []byte) (n int, err error) {
	if err := f.checkValid("read"); err != nil {
		return 0, err
	}
	n, e := f.read(b)
	return n, f.wrapErr("read", e)
}

// ReadAt reads len(b) bytes from the File starting at byte offset off.