Diagram support

You can use flowchart or Sequence as a diagram describing tool.

flowchart

Please remove back slashes \ before `

\`\`\`flowchart
st=>start: Start:>http://www.google.com[blank]
e=>end:>http://www.google.com
op1=>operation: My Operation
sub1=>subroutine: My Subroutine
cond=>condition: Yes
or No?:>http://www.google.com
io=>inputoutput: catch something...

st->op1->cond
cond(yes)->io->e
cond(no)->sub1(right)->op1
\`\`\`

Sequence

\`\`\`sequence
Title: Here is a title
A->B: Normal line
B-->C: Dashed line
C->>D: Open arrow
D-->>A: Dashed open arrow
\`\`\`

ref

https://github.com/BoostIO/Boostnote/issues/771#issuecomment-322023940