Support leaving section length unspecified in section header block.

[alnasir7]

Question

Currently, the section length field in the section header block is always filled with the actual size of the section. Pcapng supports leaving this field unspecified, i.e. a value of -1 (Section 4.1). This is currently useful for an application I am working on and I would like to open a PR for it. Would you be open to this change?

Operating systems

Linux

[tigercosmos]

@alnasir7 Sure, welcome. Please go ahead.

[seladb]

@alnasir7 are you still planning to work on it?