Description:
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When looping over and parsing multiple emails, there appears to be a memory leak. Memory is not being freed when calling mailparse_msg_free after parsing. In the test script you will notice the memory usage steadily climbing.

Test script:
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$i = 0;
while ($i++ < 100000) {
    $mail = mailparse_msg_create();
    mailparse_msg_parse($mail, file_get_contents("download.eml"));
    $struct = mailparse_msg_get_structure($mail);
    mailparse_msg_free($mail);

    echo "Memory Consumption is ";
    echo round(memory_get_usage() / 1048576, 2) . '' . ' MB' . PHP_EOL;
}

Expected result:
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Memory to be freed

Actual result:
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Memory usage continues to climb