Function parse_options 

fn parse_options(options: &str) -> PsqlResult<Vec<(String, String)>>

Handle options in StartupMessage from client

It is like shell arguments but only respects backslash-escape and space; quotes have no special meaning and are handled literally.

PostgreSQL allows both -c key=value and --key=value.

key-name is normalized as key_name.

• https://github.com/postgres/postgres/blob/REL_18_1/src/backend/utils/init/postinit.c#L487
• https://github.com/postgres/postgres/blob/REL_18_1/src/backend/tcop/postgres.c#L3866
• https://github.com/postgres/postgres/blob/REL_18_1/src/backend/utils/misc/guc.c#L6361