On Contex#FromFile return the file descriptor (it's already open by Go stdlib)

[pafuent]

Issue Description

Maybe in a future version of Echo, the return variables of Context#FormFile could be changed to return also the file descriptor, to avoid the cost of open it from multipart.FileHeader, which is already performed in Go net/http/request stdlib. The only advantage that I can see in the current signature of Context#FormFile is that the user is not responsible for closing the file descriptor, which reduces the cost of a File Descriptor leak vs opening the same file twice.

Checklist

• Dependencies installed
• No typos
• Searched existing issues and docs

Expected behaviour

The file descriptor obtained from net/http/request is return open, to avoid to reopen it later on in the caller function

Actual behaviour

The file descriptor obtained from net/http/request is Close()

echo/context.go

Line 368 in ad3be08

f.Close()

And that file needs to be open again by the caller of Context#FormFile

Related code

echo/context.go

Lines 363 to 370 in ad3be08

	func (c *context) FormFile(name string) (*multipart.FileHeader, error) {
	f, fh, err := c.request.FormFile(name)
	if err != nil {
	return nil, err
	}
	f.Close()
	return fh, nil
	}

https://github.com/golang/go/blob/78e59bb1f72c9cd16e204dbfeee05ae99a2462e3/src/net/http/request.go#L1364-L1381