Problem:
A blank line before the Content-Length header makes header parsing
fail with "Content-Length not found in header". An LF in the 'name'
state falls through to the 'invalid' state, which only return to
'name' at the *next* LF. That LF terminates the next line, so the
line with Content-Length is swallowed.
The same issue happens when a junk line is a partial match of the
header name (e.g. "Cont\nContent-Length: ...").
Solution:
When seeing an LF in the 'name' state, reset the cursor and stay in
'name' rather than entering 'invalid'.