Constant DEFAULT_APM_MAX_PAYLOAD_SIZE 

pub const DEFAULT_APM_MAX_PAYLOAD_SIZE: usize = _; // 26_214_400usize

Default maximum accepted v1.0 trace request body size, in bytes: 25 MB (26,214,400 bytes).

Matches MaxRequestBytes in the reference trace-agent, which apm_config.max_payload_size sets. This bounds the request body before any decoding, so raising it raises peak memory per in-flight request; high-volume tracers that batch aggressively may need a larger value, at that cost.