Change Details

Prefer `struct sbuf` over error-prone manually managed buf. No functional change intended. MFC after: 1 week

Prefer `sbuf_new_for_sysctl()` over error-prone manually managed buf. No functional change intended. MFC after: 1 week

Prefer `struct sbuf`buf_new_for_sysctl()` over error-prone manually managed buf. No functional change intended. MFC after: 1 week