Option::unwrap() on a None value when building vector

[FlatMapIO]

Repo: git@github.com:vectordotdev/vector.git
Build:

RUSTFLAGS="-Zself-profile -Zself-profile-events=default,args" cargo build

Error:

   Compiling vector v0.22.0 (/Users/dio/Sources/@observable/vector)
thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', /Users/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/measureme-10.0.0/src/stringtable.rs:105:62
stack backtrace:
   0:        0x103037ea4 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h98dc2850d857aca1
   1:        0x1030897a0 - core::fmt::write::h1d3d649b58373d6d
   2:        0x10302aec0 - std::io::Write::write_fmt::h06ec9f8122c8d16c
   3:        0x10303aba4 - std::panicking::default_hook::{{closure}}::h7dc5b11a4062ba26
   4:        0x10303a880 - std::panicking::default_hook::hd074d93e0c93faf8
   5:        0x10a348d20 - rustc_driver[ed0f86b0f9623b79]::DEFAULT_HOOK::{closure#0}::{closure#0}
   6:        0x10303b280 - std::panicking::rust_panic_with_hook::h9e3cdd5690e72101
   7:        0x10303b0a0 - std::panicking::begin_panic_handler::{{closure}}::h86c51084e93deeb3
   8:        0x103038380 - std::sys_common::backtrace::__rust_end_short_backtrace::h0f7c6825c91628d8

Same issue: #165