WP_Http_Curl::stream_body( resource $handle, string $data ): int

391	private function stream_body( $handle, $data ) {392		$data_length = strlen( $data );393 394		if ( $this->max_body_length && ( $this->bytes_written_total + $data_length ) > $this->max_body_length ) {395			$data_length = ( $this->max_body_length - $this->bytes_written_total );396			$data        = substr( $data, 0, $data_length );397		}398 399		if ( $this->stream_handle ) {400			$bytes_written = fwrite( $this->stream_handle, $data );401		} else {402			$this->body   .= $data;403			$bytes_written = $data_length;404		}405 406		$this->bytes_written_total += $bytes_written;407 408		// Upon event of this function returning less than strlen( $data ) curl will error with CURLE_WRITE_ERROR.409		return $bytes_written;410	}